Living Dead is a huge source of salt from me.

1= You pop it too early and you die right after it wears off
2= You pop it and the game doesn't register it and you die anyways
3= You pop it and the healer can't get you up fast enough
4= The CD is too long and isn't intuitive enough.

Just awful design really. It wasn't as bad as in 3.x when we had great self-healing but its shortcomings are really sticking out right now.