Ever been playing a game and something peculiar happens? You know this isn't part of the game because it's so ridiculously awkward and well out of place. Maybe it's a sprite that keeps occurring, or something that greatly affects the gameplay. Either way, these glitches either screw you over, or add a new dimension to the game.
I've always like the Sonic 2 glitch on the Oil Ocean stage. If you press the d-pad to the right when you break a certain pressure cap, you will miss the air cannon and land on some spikes. After losing some rings, Sonic will jump nearly three times as high and move much faster through the stage. It eventually wears off but areas you couldn't reach before are just a 60 foot vertical jump away!
On the other side, I hate the glitches that occur in Grand Theft Auto. One mission asks you to follow some guy on foot through the city. While I was tailing this guy on foot, a bus runs him over and I fail the mission. The game implies that it's my fault this idiot got run over by coachline bus. This happens on a few more missions. I'm told to blow up a truck that drug dealers are using to traffic drugs. The dealers themselves accidentally blow up their own truck... I fail the mission.
What are you most liked and hated gaming glitches?