One of the major difference between UK and US TV is the length of series. In the UK they last for seven or eleven weeks. In the US a 26 part 'season' is often the norm.
The longer season can work for 'series', where there is often only a tenuous strand from one programme to the next, such as the West Wing or the CSI franchise, but can struggle in 'serials' such as the iconic Twin Peaks, or the current hit Damages, which both seem interminable.
On the other hand, The Office was a series that was well translated to the US, but taking the original handful of programmes and churning them out as an endless formula resulted in a distillation of talent.
We are, it seems, one people divided by TV formats...