Misspelling.

The English language is such a bizarre language. I'm a pretty damn good speller. But, on a fairly regular basis, I'll type a word and stop for a second. "Wait, is that really how you spell that?"

Sometimes I'll cock my head to the side like a confused puppy, and ponder for a second. Usually it's right, but the very fact that I have to wonder about so many words makes me really hate the spelling eccentricities of this language sometimes.