What's the biggest deviation from someone's religion or faith you've seen in an individual without them ceasing to be that religion or faith?

Religious people supporting fascists particularly American “Christians” supporting Trump
- I'm surprised Trump didn't remove all the words in red from his Bible.
  But then again he's never read it and neither have the people who bought his Bible.
  
  Wait, which words are in red? I don't think I've seen that before.
  
  I have bought and read a Bible as have my parents who actually believe the thing.
- I knew a guy like that until recently kicking him out of my D&D group. There was always an undercurrent of moral superiority to the rest of us, which we tolerated because it's somewhat of a geeky trait, but declaring himself as pro-Trump was the last straw. I don't have to extend my hospitality to that.

"Christians" being borderline Racist/Discriminatory. Seen that both in classmates (a creationist) and in politics.
- Not even borderline, completely over the line.
- There's some biblical precedent for that in the parable of the good Samaritan.
  It's almost like religious brand doesn't really matter ethically.

Had a room-mate I described as a "lapsed Muslim". He took things like Ramadan VERY seriously, but then he'd drink like a fish the rest of the year.
Kind of like a Christian who shows up at church for Christmas and Easter, but blows it off the rest of the year.

A classmate of mine was a practicing Muslim. He claimed drinking hard liquor was fine cause the Quran only forbids wine and beer.
And when he did drink beer, he only did so in the basement, so Allah doesn't see it.
- That's as bad as the poop hole loophole.
  
  Fuck me in the ass cause I love Jesus!
- The excuses are even worse when people just do it regardless in turkey

Like every american evangelical who supports deportation or honestly the American empire in general. There is no way these people have read and understood like anything from the bible. Actually nuts how contradictory they are.
- Part of it is definitely also that most people in the US don’t fully understand how the American empire works, nor do they want to. We’ve been committing a genocide against Latin Americans on our soil for at least a decade (holding them in prison without the right of habeas corpus because of suspicion of illegal immigration [not always proven], separating children from parents, and sterilizing women without informing them/obtaining their consent), and fucking their governments up abroad since at least teddy Roosevelt. Add Guantanamo Bay and our behavior in Africa and Central Asia (predatory loans and stipulated aid, mostly) and the Middle East, and we’re straight up ruining the world.

Most Catholics see their religion as a buffet. They choose the things they like and ignore everything else.
- I've heard cafeteria christian for this. It really seems to apply to most religious people. They do what they want and pick and chose what doctrine works for how they actually want to live, then rationalize why that is OK. Some of that 'logic' is wild...

Met someone who - in the course of a discussion - admitted that they were adamant in their belief that God existed and all the stuff in the Bible had actually happened, but also adamantly refused to observe any religious commandments or pray, because he was "angry at God" over the state of the world.
I wasn't quite sure if I felt sorry for his dealing with that kind of anger, or mild respect for his willingness to fully believe in God and yet raise a giant middle finger in His direction. Man had a mission, I guess.
- I don't believe that there is a God.
  But if there is, I sure do have a laundry list of questions for that mfer that I'll surely be asking as I'm escorted out of the pearly gates and downstairs.

there's this 10 or more commandments this one religion has. yeah, the followers cherry-pick their fave.
there's prolly something like a list of capital sins too. yep. pure theater and master showmanship to these guys.

My aunt is a Catholic and thinks that the Pope is too woke and they should get rid of the Vatican altogether...
- To reduce his carbon footprint the current pope refuses to shit in the woods.
- She has #47 now. Who needs a pope?
  
  Ugh, too close to home lol
  
  Who says she's American?

My Muslim classmate ate pork during Ramadan. He just didn't gave a shit lol. He got someone to buy it for him like a drug deal.
- Lol, did he at least wait for evening before eating?
  
  Nah, it was during lunch lol

No idea how to rate different things.
Lots of sex before marriage. Sometimes it was okay because "they weren't going to marry them, do it isn't premarital."
Lots of accumulation of weath and doing only negative to poor people.
Lots of "throwing the first stone."
Publicly displaying religion from religions that specifically say not to do that.

I'm out here everyday not sacrificing people and everyday the world gets a little worse.
The Earth and the Sun are hungry.

Jehovah's Witnesses tend to care a lot about the origins of certain social customs. Holding up your drink and doing a toast is forbidden, because it supposedly comes from ancient Greek religious customs.
They also don't do yoga, because it comes from another ancient religious custom. However, acupuncture is allowed. You might find this puzzling, since that practice is just as rooted in ancient religious customs as yoga or any number of other things. Not only that, but yoga has some scientifically proven benefits (broadly speaking; it depends on the specific stretch you're talking about, and some are dangerous) while acupuncture is no better than randomly sticking needles in people. In general, they are very hesitant to call out health care woo, and it's led to a curious contradiction in this case.
Mind you, before I left over a decade ago, I knew quite a few JWs who were quietly doing yoga, anyway.

Super Catholic lady cheating on her husband. Then living with the lover and sending the husband bible quotes. That happens to be my ex.
- So sorry to hear that. Being cheated on is one of the most painful experiences. But it is a common thing I've seen from religious people. My best buddy found Jesus again because he is dating a married woman that is hardcore religious. They've been cheating together for nearly 15 years now. She is married to her husbands money and strings my buddy along like a puppy. Looks down on others because they don't do what she believes the bible wants. Fantastic hypocrisy right? I do hope there is an actual Hell for those type because they rarely suffer the consequences for their lack of following their own religion.
  
  You know it was a pretty awful ordeal. She had her boyfriend serve me. Plus all our church friends threw her a party. Was really painful. It helped me along to become an atheist.

Personally, I can only think of one which was my great uncle who works for NASA. He was an atheist for all of my life (30+ years) until a few years ago when he came to visit us and began coming to church and explained that he’s now a Christian.
I haven’t asked his reasons why but I am curious what led to his conversion. Most of my family is Christian, but no one, as far as I know, pressured him to change or mocked him for his (lack of) belief. The topic of religion never came up in family gatherings besides having a circle of hands and prayer before dinner.
- TBI?

I knew a Jewish guy that loved bacon and pork chops in high school.

I'll start with fellow followers of Christ and say a lot of the ones I've met aren't as easygoing as would be stereotypical. Now you might read the Bible (or the Book of Mormon, or the Book of Hagoth; I have 'em all) and think "hey that person over there is famous for their devotion, I'm going to strike a friendship" and then realize it's a lot closer to "stepping on eggshells" than you might think. Points to other Hagothists/Mormons though as they actually have been understanding people. Gossip, hate, whatever you want to call it, I'm no stranger to bearing witness to it, and you often wonder "wait, why are they involved in this". It's also complicated because, by the same token, they have positives like what we might call tolerance towards the LGBT, so there are other dimensions to it.
Technically not a "religion" per se, but the atheist situation strikes me as odd. It often seems like their attitude towards adherence to God is second-hand because what they'll say about God they'll never say about government, or they'll do it rarely. Everything to most of them considered "questionable" or "concerning" is only "questionable" or "concerning" when it involves divine authority. I have joked before that if climate change or Marxism was in the Bible, nobody would believe them.
I also noticed a lot of Buddhists couldn't quote sutras from the Tripitaka or don't follow them to an extent where the individuals are Buddhist-esque enough to rely on to be peaceful towards your dilemmas, almost as if it's for show. Heck, I'm not a Buddhist yet can quote sutras that aren't in the Tripitaka (because not all of them made into the final edition).
- I don't follow your atheist paragraph. Could you clarify a bit? Are you saying that atheists disbelieve the contents of the Bible simply because it's a holy text, even though some of it may be factual? (E.g. historical events)
  
  It sometimes seemed that way. It's not as common now for the discussion to come up in the 2020's (maybe someone gave them what they were looking for, considering the opposite is now trendy), but it was common for them to say, for example, that they require some kind of physical trace in order to not hold God in doubt but not carry this over for things like historical figures.

Baha'i that adheres to reincarnation? That's just another faith waiting to be spread!

Disclaimer: I’m not Muslim and didn’t grow up around many Muslims, but I now have a lot of contact with Muslims of varying strictness.
The phrasing in the Quran is not perfectly clear, but there are a few interpretations: all intoxicants are banned (including laughing gas, alcohol, and various medications); plant-based intoxicants are banned (including alcohol, Opium, hookah, tea, and tobacco); or intoxicants made from grapes or dates are banned (so vodka is fine).
I used to work at a hookah bar, and was always surprised that Muslims generally believe tea is fine (caffeine is an intoxicant), frequently believe hookah is fine (nicotine is definitely an intoxicant), and generally believe alcohol made from other sources is not okay. This seems like picking and choosing to me, but even the Muslims I know who drink tend to fall into this category and just feel guilty about it
Unfortunately, I am not delicate enough to seriously discuss this without offending people, so I don’t know why. I assume cultural norms outweigh the actual scripture (which happens with most religions and which I don’t think is necessarily a bad thing, but I’m generally in favor of harmless cultural norms and non religious).
The one that seems to me like the biggest deviation, to actually answer the question, is when pro-life christians are for the death penalty or hawkish about wars.

There's an inside joke about Iran that after the Shah was deposed, the only thing that changed was all the illicit activity happened inside instead of outside.
Its pretty believable considering you can find plenty of Muslim Iranians who openly drink and party, hence why they're actually the least likely to be seen amongst a group of Muslims.

A couple of my friends eat bacon, have a Christmas tree, etc. and say they're Jew-ISH lol.