Bug 1: Floating grass. Grass would float over pools of water.

Bug 2: Multi-enchanted books. Books would spawn in chests with multiple enchants; I got a book from a mineshaft chest with Power I, Respiration II, Sharpness III, and in my hot-bar, the entire spot was an enchanted particle affect instead of the item itself having the enchanted particles.

Bug 3 affecting all Minecraft versions: Floating blocks/sand. PLEASE fix this, it takes the realistic feel away from Minecraft. Script it so if a clump of blocks isn't connected to the mainland, it disappears. And script it so if the game registers that a block of sand has nothing below it, it falls (including grass or flowers.)