As a Scotsman, not cursing messes with my impression that they're real people.
Into Darkness was great for adding 'shit' into a scene. Kirk's reaction to Spock in 2009 was a little off, not for the word, but the performance, which mirrored the Data line. But when Carol Marcus is seconds away from blowing up? Perfect moment.
I have met and known many high profile professionals, extremely intelligent people and I myself have a vast vocabulary (to the point where, despite not being it in the slightest, I'm often seen as the posh one in a group - if far from the most intelligent), and all of us utilise the fine art of casual F Bombs. Which aren't really bombs. More light taps on the shoulder. I'm sure it won't make anyone less civilised to slip out a 'naughty' word.