from watching a number of his shows on both bbc and american tv, i'd have to say that while the foul language seems just to be his normal speach, the nasty attitude is a schtick. it's a total put-on for tv. much worse, or really more sensational for american tv.
he's a big, fit guy so he's able to intimidate a lot of people and plays that up for his shows. he is a bit full of himself.
i've seen him curse in front of his 4 kids on one of his shows, so that seems to be normal for him, but he also seems to be a good and loving dad.
the only thing i don't like about him is he says yeah or yes to solicit a response too often. it's annoying in the way someone says "you know", "umm", or "right now" far too much.
in nomine patri, et fili, et spiritus sancti.
Meh nom eh noh...doot dooooo do do do.