Actually, even though Dollhouse had better episodes and worse episodes, I would hardly say any of them were 'bad', so I'll stand by ... well, everything Whedon has ever done:
Buffy
Angel
Firefly
Dollhouse
Fawlty Towers
Twilight Zones (not just the original series, I like prety much anything put out under this name)
Outer Limits (ditto)
At this point I should add my qualification: notice, they did not say, 'mediocre'. They said, out and out, 'bad'.
That said, I'm not sure I've seen any other shows in their entirety. Saturday morning cartoons, perhaps?
Batman
Castle
(yes, it's just a procedural, but damn, it's the best procedural I've ever seen)
Driftwood
Veronica Mars
Mongrels
Archer
Deadwood
Sports Night
Liquid Television (yes, really)
Aeon Flux (technically, not its own show)
Beast Wars
Backyardigans (what can I say? I love childrens' television and movies)
Reboot
Pee Wee Herman's Playhouse (yes, really -- stands on its own)
...which puts me in mind of:
I'm surprised no-one has said Six Feet Under yet. (haven't seen it, myself)