Misfits and Heroes

I've been trying to figure out why a lot of reasonably well made TV is unwatchable crap. The main problems are poor dialogue and too much exposition (often the source of poor dialogue). i consider both to be dumbing down or condescending. Sometimes it's just poor music (I find a lot of BBC productions have poor/predictable incidental music). There most be more though...

Rob Delaney was on BBC Breakfast recently. He explains differences between UK and US humour.  For professional comedians, there's no difference. We're both as funny as each other.  On an every day level though, Brits are funnier than Yanks.

I wonder if this is why I consider New Tricks to be watchable crap,  CSI pretty much unwatchable and CSI Miami made me shout at the TV when I tried to watch it. Perhaps the American stuff really does represent relatively humourless everyday interactions and this is simply a cultural difference.

Perhaps this is the difference between Misfits and Heroes. The difference between Sheldon and Howard?