It's bad when you just fall right through the platform. As far as a platform being a centimeter away, I think Braid plays on this pretty well, simply because you can rewind everything until you get it right. But that doesn't fit everywhere.
Make one of those annoying platform games where you jump from one platform to another, and then make that one platform that the player always misses by a centimeter.
Have a boss.[/quote]Imagine MegaMan without bosses. Imagine Shadow of the Colossus without any colossi.Make Duke Nukem.[/quote]Duke Nukem 3D? Duke Nukem Forever? Or the old Duke Nukem platformer?Make a Game Named Ratchet and Clank.[/quote]You really don't like platformers.Make it where the player has to find a key. You search ten minutes for a key when you could've blown the door open.[/quote]Try it before you pry it?Have annoying cutscenes that you can't skip yet have nothing important in them.[/quote]Unskippable cutscenes belong in 1997, and they didn't belong even then.Make a game where you have to play in the same place every other freakin' level.[/quote]Pong?Have a boss where he isn't even hard, just where hundreds of enemies decide to come out right then and shoot at you. All of a sudden, when the boss is dead, they stop and go away.[/quote]At least, let the hundreds of enemies have some connection to the boss where it makes sense that they're gone too if the boss is gone. It's cliche, but it works.