I think the worse one was The 4400, which managed to drag me into four series and then, the end. The fifth and final series never happened. That's 64 hours of my life I'll never get back. That and the infamous Firefly, which must count as one of the worst ever broadcasting decisions ever (I mean, whether or not you liked the programme, how fucking much would they have made out of sales and eternal syndication). Sadly, like estate agents and STDs, US network execs seem curiously resistant to modern life and persist, along with their obsession for 22-episode series when there's enough material for six and then somehow being puzzled when the audience drifts off. Combined with utter thrall to ratings and retaining advertisers, even when it's obvious they'd stand to make a lot more from non-advertising revenue. Which is, of course, why Netflix is belatedly ascendent.