It's embarrassing to admit this, but something has happened to me here in Terokkar Forest that hasn't occurred since my apprentice days.
Occasionally, my spells will fizzle when I know I've done everything correctly. I almost drove myself crazy the first time it happened.
I think I've found the cause. The forest is full of creatures called warp stalkers, demonic creatures with an affinity for magic and a habit of disturbing magical flows. The best way to deal with them is simply to kill them.
<Andarl dabs at his forehead with the sleeve of his robe.>
Thank goodness. I was beginning to wonder if the things had displaced the rest of the forest's creatures.