What I remember most from my first Fallout 1 play-through is trying to rescue Tandi by myself without armor and without realizing that Ian (or anyone) was recruitable. I think I had a 10mm pistol (with AP rounds, no less) and figured that I could swipe some armor and stuff from the gang, and I'd be able to Dirty Harry my way through them.
Six or seven deaths/load-games later, I figured out I would have to go find more firepower and more armor before tangling with them again. lol
Also got my ass handed to me in the cave with the radscorpions more than twice. They figured if I didn't need armor, then they didn't need poison to kill me. heh
Then once I finally hired Ian, I found out he was more likely to help kill me (with the SMG) than help kill my enemies. I can't count the number of profanity-laden tirades I launched into while re-loading the last save, as I refused to tolerate such obvious "bullsh**" as one's companion being so stupid time and time again. I was trying to restore as little as possible otherwise, but I couldn't put up with such blatant (game-design) stupidity. (The game was too brilliant otherwise to stop playing; one had to overlook that and the NPCs blocking you in on occasion.)
The biggest problem I remember having with Fallout 2 was just not being able to figure out how to help Torr with his quest; I always said the wrong thing to him at first and then was never able to get the "protect the brahmin" quest. (Oh, well, and then there was the problem of having my boots melt in the toxic caves and not having enough health nor healing stuff to get back out. Ouch! That, and I didn't know how to stop Sulik from running in to battle three goldens at once and dying on the goo - until finally I realized that I could disband him without losing him permanently, so that I could leave him far away from the goo, and then lure the geckos out of the goo and over to where I'd left him.)
@Hassknecht: Fuckups definitely are fun. Games without any real danger of screwing up and dying are not nearly as exciting to play. Fallout's unforgiving nature is one of its real strengths: walk into the wrong place or piss off the wrong person - and you will pay the price. Makes you have to think more, plan better, weigh the risks vs. the rewards.
m-