One story that sticks out in my mind is when I used to play the old Star Wars D6 game.
The group set up was that we were all part of a Rebel Special Ops group, code name Target Group. Now,before I continue, a little background. The GM was a total Jerk. Wouldn't let anyone really accomplish anything and had to prove just how big his d....ego was. Even if you rolled heroically, you still barely got by and it seemed that no matter what you did, we failed more than we succeeded. Not to mention that he made us use the template from the book to create characters, the ones that are VERY under powered, instead of using normal character creation rules.
Anyway, we start the game on our way to Yavin 4...yeah right after some farmboy took out a large piece of Imprial real eastate. So we get ready to depart yet again but find out that 13 Interdictors have sealed off the area. So, long story short, we spend 6 hours trying to make up some sort of defense to the eventual attack. I, as the team's demo expert,cant even get some extra power packs to jury rig some IEDs. So after sweating out an entire session of feeling useless, we are conveniently resqued by said farm boy and some hotshot smuggler. We do absoluitly NOTHING.
And why? Because we were playing at the GMs house who hung that fact over our heads.
I hate GMs like that.