1. The original Amiga mouse that collected tons of sh*t on the mouse ball. It made playing games like Lemmings and Cannon Fodder really frustrating. You also had to apply a ton of pressure on the mouse buttons for them to register anything.
2. The 'brick'
3. The black 'write protect tab' on floppy disks. You needed to have finger nails like a 'tranny' to move it.
4. Trainers. They totally de-value the playing experience. Why play a game if you can get to the end very easily?
5. The b*stard who broke into my house while I was on holiday in 1997 who stole my Amiga 1200 with Blizzard 030 MK IV.
Erm, thats it I think.