It's possible to get inside a boat/minecart from a further distance in creative mode.

Enabling VBOs can make the game (almost) irreversibly unplayable.

Crash when trying to place a torch on the bottom of a block

Ice blocks' breaking animation color ignores translucent/transparent blocks, including itself

<Nevermind>

Killing a mob being ridden by an item creates an unretrievable item

Crash when spawning many silverfishes.

Mobs behaving strangely, spinning.

Flickering ghost blocks