This is all good info except for the gender thing. The round/long difference is just a growth habit. Watermelon plants (and other cucurbits like squash, zucchini, cantaloupe, etc) produce male and female flowers. Only the female flowers produce fruit and must be pollinated by a male flower to do so.
FYI there is no reliable way to tell if a watermelon is ripe after it is harvested. The most reliable indicator is the tendril on the node the peduncle is attached to. When it is fully dry, the fruit is ready.
The markets where I buy are confident enough in their product that they cut the one you want to taste before you buy. I've never found a more reliable method than that.
I spent a season working in a packing house for watermelons. They'd come in by the crateload and we were allowed to just grab one to eat any time we wanted.
The trick I was taught, and which proved to be pretty reliable over the course of the season, was to feel the veins. (This is possibly what's being described as webbing here?) Watermelons aren't smooth, they have wide "veins" running top to bottom and you can feel them if you put your hand flat on the side of the melon. The bigger/poofier/wider the veins, the more ripe is it.
I'll just remember "pick the most fucked up looking melon with patchy orange spots and ugly crisscross webbing". It's probably not going to make the photo reel but it'll taste good.
None of these visual methods are reliable as these things differ greatly amongst melon varieties. The easiest way is just to knock on the watermelon like you would a door, if it sounds hollow on the inside, then it's ripe.
This I know to be the only reliable method. Also after knocking if you squeeze it it should make a sound as something rigid starting to crack not as being rubbery/ elastic.
I dont know about watermelons but there are a plethora of plants that can not produce fruit without being pollinated by another plant. Also if you ever self pollinate a plant you'll have to recognize the 2 different parts. Is it just the calling them male/female that bothers you?
Edit: I guess I should say plants/flowers can have a sex, fruits I don't think would. They are just seed dispersers I believe.
Why the green arrow for the "wrong" one, and the red arrow for the "right" one?
3 of the 4 items (gender doesn't matter, variety does) are generally correct.
Source: I'm a former watermelon "cutter" (the guy that goes out in the field first thing in the morning and cuts the good melons off the vine, and turns them belly side up so it's obvious to the field workers which melons to load up)
Also, with the whole thumping thing, most people just look silly doing as they don't know what they're doing. If you do thump, ones that have a higher pitched ping are still green, and that have a really dull/flat thud are over-ripe/too gritty/sugary. Also, weight should feel right, too light and it's overripe/rotten.
In general, any melon sold at the store should be good, just take one and stop trying to be a hero. At least the farmers I dealt with are pretty ethical, they aren't purposely shipping bad melons. It just takes experience of seeing/handling melons for a while to get the "picking one" correct. Most store I know of have a satisfaction guarantee anyway, take pictures if it's bad and when you go back get a refund if you're that concerned with it.
I don't tap, I just smell them. Am I being a dumbass?
I don't smell half a dozen and try to select the best, rather - if they don't smell sweet ill probably get something else and leave the watermelon for another day.
On oranges, damage to the fruit (insect bites, cuts, etc) often cause the fruit to be sweeter in the area of the damage. So ugly fruit is often tastier.
Americans especially are sold shiny pretty consistent fruit. Ripe fruit is browning, wrinkled, lots of flaws. After a while you'll see some of those "flaws" as signs of tasty fruit.
I'm a produce manager for a grocery chain in the SE US. I tell people ALL of the time to pick out the ugliest cantaloupe/honeydew because it's typically going to be the sweetest/most ripe.
You'll have people shaking, rolling, knocking on melons trying to find "the good ones". It's pretty funny to watch people make their selections.
Morgan Freeman taught me to flick melons to determine the ripeness in Unleashed, and I have honed the skill to a masterful level. Get weird looks from strangers sometimes tho..
Honestly, I actually prefer the bigger, firmer, less sweet watermelons over the smaller, softer, sweeter ones. I don't like how the small sweet ones sometimes have a slightly mealy texture, and prefer a lot of cold watermelon texture with a bit of the sweet melon flavor over a smaller amount of melon with a flavor that can be a bit more intense than I'd like it.
Watermelons are the closest thing to biblical mana in these times of extreme temperatures. I too aspire to become a watermelon wizard, but for my own benefit.
There's some tools take them easy to prep. I have a tool that's just a metal loop and it's amazing. Basically you just slice the watermelon in half then scoop out in either sphere shapes or long strips.
I'm not sure what the effort you're taking about is. Don't you must cut off a hunk and then cut it into chunks? Seems like one of the easier kinds of produce to prepare.
I worked at a grocery store and the old timer who trained me in the produce section said that all you needed to find the best watermelon was learn how to give it a slap and if it sounds like a basketball that's a good watermelon. Learning the slap takes some practice but when you do it right, you'll know.
Man, coulda used this a few days ago when I got a watermelon for the fam - I remembered the color of the spot part, but had forgotten the other things to look for 🤦🏽♀️🤷🏻♀️ the one we got was decent, but coulda been more flavorful imo