"The one error that throws me out of a story is lose/loose.
He was afraid he'd loose his life if he didn't set the wild badger lose."
This is definitely one of my pet peeves, as well. It drives me crazy when I see things like "I'm afraid I'll loose the evidence." Arrgh!
Also peek, peak and pique. I peek through the knothole.
The climbers scaled the high mountain peak.
She indulged in a fit of pique.
The circumstances pique my curiosity.
Nan