Storytime:
It's 1997, I play a game that my uncle shows me on his Playstation 1. There's tons of reading and a weird fighting system but it seems really awesome and has some amazing FMV scenes. He tells me I'm too young to play it and won't let me borrow it to keep playing... So I go to blockbuster and rent it for a few days.
I remember the back of the instruction booklet showing off one of those memory cards and saying "try beating the game without one" which is exactly what I tried to do, because I didn't have a memory card! Then my mum turned the game off when I was at school one day and we had to take the game back to blockbuster after a couple of days. Damn I lost all my progress!
ADAMANT that I would play this game I got my own copy after swapping for it at my local game store and got my own memory card. Finally I could save my game and not worry about losing my progress. The game continues to challenge me a ton and I don't really understand how the systems work but I'm 10 years old and having fun so who cares.
I figure out that I can buy grenades from the shops and I use that as my main attack for awhile... at least until I get to the big city with the gun on it. Buying and using healing items is such a pain all the time though but thankfully money isn't hard to get.
Fast forward further into the story and one of my characters has to go one on one with another dude, this is like that other fight with the guy and his dog when I didn't have 3 characters that could throw grenades and heal! I can't beat this dude with the gun on his arm with just 1 guy!
... Then after failing over and over again, I finally figure out what putting "Restore" on his weapon does... then I figure out what putting "Fire" on it does...
Suddenly the FF7 materia system clicks into place in my brain and about 15 hours after the tutorial teaching you how to do it I figure out how to play the game.
Still my number 1 game of all time to this day. And I never forgot how much trouble Dyne gave me that first time playing through the game.
tl;dr I didn't understand how the FF7 materia system worked until about 15~ hours into the game and was using grenades and potions for all fighting and healing for a loooong time.