I admit some days I swear too much at work, and at some times I'm ashamed that I fall back on one adjective and two descriptive nouns (although the people thus described probably deserve it and don't get me started on Excel), but I find excessive gratuitous swearing jarring and somewhat boring; it's like you're adding extra words to a sentence just because you want people to know this is a 'gritty' setting. Most languages are versatile enough that a little bit of thought can produce something grittier and more invoking.
On the other hand, it is equally jarring when a swearword should have been used but has been toned done, no-one has ever said 'frak' and not sounded ridiculous. If you want a laugh, track down the ITV edit of Robocop, produced to show the film on a Saturday afternoon. "Frag you, mothercrusher."