I'm always surprised and somewhat suspicious when normies talk about these old games with fondness, considering how difficult they were. People talk about how challenging games like Dark Souls are when they basically have no death penalty, when in comparison these old 8-bit games required you to beat them in a single sitting and losing all of your lives meant a complete reset. I played Super Mario Land on the gameboy for countless hours as a kid and never finished it; got to the final area and boss a few times but inevitably died and then it was all the way back to the beginning.
Part of the enjoyment was having the game beat you.
I recall about the last time I played Mario 3 as a kid I had an awesome run, chalked up a ton of lives, then blew them all on one of the last levels in the game that I'd never gotten to before that was brutal.
Ghouls and Goblins was another my friends and I loved. It was too brutal for any of us to want to waste a birthday present on, so we'd occasionally rent it and have a mix of enjoyment from progressing a little bit further that time if we could while respecting it as a merciless game.
Battletoads too, which one of us owned. We'd play it for the short amount of beat em up fun and a chance to see if we could always get by the first bike level. If we did it suddenly got serious with everyone glued to the screen wanting to see if we could get to a hiher level and see newer stuff.
Keep in mind, kids play to dick around and have fun, why FFVIIs minigames were so beloved, not to be completetionists, but if you happened to get a little bit farther in a tough game it was some icing on the cake.
Everquest was like tha too in it's own way, in that if you weren't a goo enough players or socially skilled to work yourself into a top tier guild you didn't see shit or get good items. Even being in a 2nd or 3rd tier guild had your guild waiting until the top one on the server was done with content and moved onto exclusively the latest stuff. My old RZ guild finally got into doing NToV well into Luclin.
You have to realize, fondness for things and enjoyment don't always come from achievement, IMO, much of it comes from anticipation and investment. Any game that gets you hooked on wanting to see the next level of dungeon and you are stuck having to wait and work on getting better at the game will produce an attachment and love from the player, just as anything else that does those things brings that out in human nature, from work to relationships., etc.
For the record: the most brutal game of all time is Battletoads. Anyone who said that finished this game without using ROM and emulator is a liar.
It was one of those game's you waited for the local game stores Game Genie to be in to rent specifically to play with.