There are always things I don't like in nearly every episode or film, but none that I particularly hate (except perhaps "Shades of Gray" for being a clip show).
What I do despise is the current trend in television to "reality" shows. They always have some sort of writing staff comprised of people with no previous credentials. Legitimate actors, directors, and other professionals don't get work. The only reason these shows exist is because it's cheaper for the networks and studios producing them.