Have yet to have anything like these happen to me. 13 year MMO veteran, not much stumps me anymore.... I have on the other hand helped a ton of people in game, which is hard when you have only been playing for 3 months. Most of them bite me back in the ***, I receive no thanks, or that person never logs in again... Yea, I friend list everyone I have helped, most of the time they might need help again later on.
Sometimes I might ask myself why I even bother, but some of the best times I have in the game is while helping other people. Sometimes it will even build a friendship, some that can even last many many years ( I still talk to people I have helped out in other games I have played over the years
Not everyone is out there looking for a power level, or free credits. Even if you just answer their questions which might seem stupid to you can have a major impact on their game play, which in the end will make them not only stick around, but make them a better player for later on!