You still watch them in reruns and enjoy them. That is the key. Or that one show you seek out online and watch an episode or two. Yes, animated shows count here. Why not? They fit the criteria of sitcom.
http://www.ranker.com/list/tim-and-_39_s-top-sitcoms-of-all-time/obrien-news-service,
Cheers
Family Guy
Family Ties
Fawlty Towers
Seinfeld
The Bob Newhart Show
The Dick Van Dyke Show
The Golden Girls
The Mary Tyler Moore Show
The Simpsons