The actors used to be so deadpan but now characters like Dave and Denise deliver a lot of their lines with a stupid smile on their faces that make them look really idiotic and even borderline retarded at times.
About last year I bought a boxset of the first 3 series (which was every episode ever made until the 2006 special came along) from Morrisons for the amazing price of £5.99. I'm so glad I didn't buy any of the others since then - not even 'The Queen of Sheba' which was £2 at Morrisons.