This show is an all time classic and it's easy to see where more modern shows, especially such total and blatant rip-offs as the Simpsons, have their roots.
Married came about at a time when all other family sit-coms were sickly-sweet and correct. Who can forget such horrors as the Cosby Show or Diff'rent Strokes? Married was different. It dared to push the envelope of what was considered (at the time) right and proper. The family wasn't nice to each other all the time (or even any of the time!) and the show had a more real feel to it as a result.
Of course, reality quickly became subjective in Married, as the episodes became ever more ridiculous and crazy. But every show pandered to some aspect of family life that we can all identify with - car sharing, hatred of our spouses relatives, puberty, dating, work etc. etc. The list is endless. If it's a real life issue, Married has spoofed it in some way or other. Nothing was sacred. Even PMS! Though the writers were reigned in a few times, by all accounts.
The show ran for eleven seasons and over 250 episodes, which is pretty incredible for a comedy show and really should give you an indication of the dedicated fan base that Married attracted. I suspect the show will be in re-runs somewhere until the end of TV as an entertainment medium.
For more info on the show I recommend the E True Story documentary on the show, which really gives an insight into how the show started, progressed and finally was cancelled.