My favorite game glitches of any kind were always in San Andreas. I like seeing random glitches when it's not annoying.
I had a glitch one time when I was on a killing spree, and all of a sudden when I hit 5 stars, as I was firing my weapons, they started shooting faster, and my bullets were unlimited for some reason. Great glitch when you have cops coming from all directions.
I think it was because I input cheats very fast as I play.