Indeed. I recently found this piece of code:
if (X) assert(false); // we never do X, ever, anywhere.
if (exact same X) { do_useful_stuff(); }
Did you update the comment? :-)
// there are two kinds of mutually exclusive commentors
enum kinds { writers; readers; updaters; }
Outdated comments are often way worse than no comments, because they can give you wrong ideas that aren't true anymore, and send you off in the wrong direction before you finally figure out the comment was wrong.