While I agree that most of these shows are not so good, I ask you to consider some white shows. What was so good about Friends? How I Met Your Mother irritates me. Two and a Half Men is only good part of the time. Mike and Molly - not soo good.
Rock was very good.
Bernie Mac had a run of some very good episodes, although some episodes were not so good.
In Living Color was a great show. Like all comedy skit programs, they could not all be jewels.
Everybody Hates Chris is no worse than the average run of sitcoms.
Moesha had some good stories.
Cosby was as good as they get. Most people don't seem to recall that Bill had a show in which he played a high school coach. It did not stay on that many episodes, but I liked it too.
Julia was too saccharine for me.
The Nat King Cole show was very good, if you like variety shows.
Martin could be funny at times.
Flip Wilson had a great run.
Can't recall the name of Damon Wayans' show, but it was sometimes good, sometimes dull.
There are a number of these shows I have not watched and a few that were not so bad I can't remember just now.