I'm surprised to see this node has a negative reputation -- I don't disagree strongly enough with it to downvote it, but I think it sets the 'you must comment!' bar a little high.
I agree that code/comment mis-matches is a problem -- in that case, I'd rather have no comments than bad comments.
Writing down comments on edge cases doesn't make the code more concrete -- comments don't change the code.
And I disagree that .. the writing of good comments is not a distraction or an overhead; if the comments get written during development, that's fine. Having to go back and add the comments afterwards is definitely overhead. Sometimes there just isn't time to spend a leisurely week adding comments and generally tightening code up.
Pull out some code from CPAN (say) and critique it for us .. we'll be glad to give you some feedback. :)