True enough, but there are actually criminals dumb enough to telegraph what they're about to do on Facebook or whatever, then it happens, and then the police know exactly whose door to knock! But yeah, obviously if you talk shit like that, you've no intent on carrying it out the vast majority of the time, with rare exceptions being if you're that dumb of a criminal and are brazen enough to leave online public evidence of the planning/premeditating of a crime, assault/battery or whatever, etc.