According to the IMDb trivia page, the F-bomb is dropped 126 times which is less than two-per-minute. How can that be considered excessive?
I did think it was interesting, with the children's fantasy film set being an important part of the plot, that four of the In Bruges actors are in the next Harry Potter film: Ralph Fiennes (Lord Voldemort), Brendan Gleeson (Mad-Eye Moody), Clémence Poésy (Fleur Delacour) and Ciarán Hinds (Aberforth Dumbledore).
Make that five if you count Stephanie Carey who played the Canadian wife/girlfriend and is an uncredited stunt performer in the Deathly Hallows. You could even stretch it to five-and-a-half, if you count the fact that Brendan Gleeson's son Domhnall Gleeson plays Bill Weasley who is, strangely enough, engaged to Clémence Poésy's Fleur Delacour character.