Finding clean water was a constant, grinding kind of problem in 'Fallout'. You'd think with all the pre-war tech lying around, it wouldn't be, but no. The first real fight I got into wasn't with a mutant, it was trying to barter for a few un-irradiated bottles in Junktown. That sets the tone, really. Everything is a transaction, and your vault jumpsuit might as well be a target.
Then there’s the psychological whiplash. One minute you're in the sterile, predictable vault, the next you're watching a man get torn apart by giant ants. The game doesn't hold your hand with that adjustment. Your character just has to swallow the horror and keep moving, which maybe makes you a little harder, a little more like the wasteland yourself, by the end.