I can relate to Sephex's misfortunes in Super Mario Kart. I was hit by my friend when he had a star, I was then hit whilst stationary by a stray green shell, during which time my friend had happily picked up a red shell and was bearing down on me... I was not happy.

During a 100% speed run of Zelda: A Link to the Past I got a bit too penisy on the boss of the sixth dungeon in Dark World. I decided that switching items in order to use a red potion would take too much time... bad move.

Playing Super Dunk at the Golden Saucer in FFVII. Getting up to 150GP with one final shot to "Double up". Then dropping your shot short of the basket... the actual pain.