Now comes the argument of "but to leave it out is not realistic." There are moments in writing when using any words simply will not do. For instance, when Indiana Jones was standing on a rope bridge spanning across this deep canyon and the bad guys were at either end of the bridge, it would have been unrealistic for him to say "oh fluffy muffins." So, Mr. Jones lets out a curse word, after all, who wouldn't; however, it is noted that out of the entire movie, that is the only time he uses profanity. A rule of thumb is, if you can think of something better to say, please do. The overuse of these colorful expressions take the audience out of your story.
Should you insist that there is nothing wrong with the proliferation of profanity in your work, ask yourself this, would you want your boss to read it? Your mother? How about your pastor/priest/rabbi/etc? No? Then why use it. Use your creative writing skills to come up with better language than that.