Why do the best sitcoms and tv-programs never last while rubbish ones do?

Question

things like summer heights and the big bang theory were awesome but ended so soon. and many others. why do things like this go on for such short time. while poor soaps and other rubbish clogging up our screens go on and on.

Answer 1

idk i wish avatar hadnt ended but it did

Answer 2

Frequently, this pehenomenon can be attributed to one of three factors:

1.) The show is smarter than the audience is.

2.) Lack of promotion by the network.

3.) A good program is trapped in a lousy time slot.