It's cos there is a season break over Christmas in America - Buffy was the same. So they make the first half or whatever, then there is a break (presumably in America this is full of Christmas tat) then they make the rest of the season's epi's. With 22 episodes a season, I reckon they need that break :)
Like last night's epi - I don't think the old Patick would have gone so far with manipulation, do you lot?