Ever get the feeling that many of the the people in the Fallout world are bipolar or something? Ever have the girl in Megaton walk up to you and give you gifts? First she tells you how awesome you are, then if you try to talk to her again immediately after that, she blows you off. Most of the characters will do that... They'll walk by and say 'hi' all nice to you, then if you try and talk to them, they're like... 'F off dude'. lol (Spoiler>) My favorite was the quest for Lucy West. She's all freaked out and begs you to help her... Then after you risk your life and go through all this crap to help her, you come back and she acts like she doesn't even care anymore. lol I'm convinced that a guy programed it that way on purpose, as a joke. Too similar to real life.
I know all this stuff happens because of the limitations in programing, but it's just sort of funny.