The sad part is I like to cuss and what not. I don't like to talk all calm all the time. In fact as I am getting older I am slowly getting calmer but my voice and tone still gets taken as me offending them with my bluntness.
I get the whole be good to others but sometimes I just have about 1 fuck to give in a day and I use it for something that I think I really do give a fuck about.
Context matters. Some concerns require a certain amount of professionalism. If you're just shooting the shit with someone, shoot the shit. Sometimes a guy just has to put their work clothes on. Especially if you want to get or see shit get done.
One mistake some cultures make is assuming those using relaxed language are somehow inferior intellectually. One of those crazy myths people believe. I've yet to meet a millionaire who doesn't fucking talk like this sometimes. And the smart types I know wouldn't waste their time giving a fuck about minor details.