I think the way he attacked that poor Romulan guy who basically sacrificed his career so he could let the klingons live was boorish at the very least, and a bit despicable. It would be like someone coming up to Mother Teresa and saying: "Hey, don't force your occidental values on us!"
Oh man I agree, that poor guy! Worf is one of my favourites, but I disliked him in that episode. Also that the crewmen felt the need to lie about his ancestry shows that not everything is rainbows an puppies and tolerance, even in the "utopian" Federation you are apparently still judged by what your ancestors were...
Plus the idea that the Klingons can only be one thing and that's it is a bit narrow-minded. I mean, they're supposed to be superior beings, not insects who know everything at birth. We have our Samurai and our Hippies, why can't the Klingon? Worf is nothing but a bigot, at least in that episode.
^ This. But it's the same with Vulcans, and Ferengi and so on. ST is a bit bad about showing us culturally varied alien races.
With Worf I always had the impression though that he tries to "be Klingon" with all his might to "compensate" for his human upbringing. He actually has quite a naive, rose-tinted idea of Klingon society, which is far more back-stabby and political than the "honour-bound, brave warriors" he envisions them as.