What TV show would you love to see make a comeback if it was possible?

So many TV shows end usually either because they have not got enough viewers and it doesn't seem to take off or because they feel that they have reached the end and couldn't possibly continue the show.

When a show is canceled usually if it is a show you really liked you often can not understand why it was canceled or why it ended and would love to see more from that show.

If you could have any TV show make a comeback, what would you choose?