Both Russell T Davies and Steven Moffat are brilliantly hilarious writers, let's make no mistake about that. They often employ really silly humour into their work, and let their actors bring colour to the scripts. Davies's Doctors were knowingly brilliant, and so Davies used this as a point of fun. He also used subtle sarcasm in places ("Donna, you don't know how to change a plug"), as well as using pop culture and dry wit. Moffat's humour though is definitely more zany and often a bit ruder, but fairly similar to the template Davies laid out. Both employ a lot of comedy too; no episode is too sad or serious to slip in the odd joke, and both often include gags to contrast against the darker themes in Who. They're easily the two funniest writers of New Who, aren't they?
