As it's getting right on my tits.
In 'active' threads (could be elsewhere, but this is the main way I view) a thread might only have one reply, but it'll say 2 on the list, as it's counting the OP too. Don't know if there's a way to discount the OP in its count, or if the 'replies' column should be changed to 'posts' instead.
Just a teeny thing, but it really frigging irks me!