Hired over a dozen engineers in the last couple years - swearing is a cultural signifier for me. It's a (small) cue that you might be a good team fit. If you say "fuck" while interviewing with me, I'm slightly more likely to hire you.

While I like your style, it's very hard to ascertain that swearing would be ok in an interview with you without some prior clue. Then again, I live in the States and most of my interviews that I've gone on were all corporate jobs.