Clumsy Hands

Slippery fingers. Every time you pick up an item with your cursor in an inventory, there is a chance (8% by default) that it slips out of your hands and drops on the ground instead. A left click drops the whole stack you were about to take, a right click drops half of it. Crafting result slots are not affected, so crafting stays reliable.

Bleeding. Breaking any block with your bare hand has a small chance (1% by default) to give you the new Bleeding effect. It lasts 10 seconds and deals half a heart of damage every 2 seconds. Using any tool, or being in creative mode, avoids it entirely.