Went on too long? Mr. Pickles. I like the show but it continued on past the third season as Momma Named Me Sheriff and it is significantly worse. It just feels like one of those generic crude humor shows by Roger Black and Waco O'Guin that Netflix pumps out.

There's also How I Met Your Mother and Two and a Half Men.

Ended too soon? Jeff and Some Aliens. A great dark comedy cartoon that I have rewatched several times.