Standards also vary a lot between different societies, areas, social classes/groups, etc. People are probably a lot more exposed to each other now, and have plenty of chances for their expectations of one another to conflict.
Personally I tend to steer clear of being disgusting, but I make no effort to avoid swearing and I speak very directly about things regardless of how sensitive the topic might be. I'll also find humour in virtually anything, as long as I can do it without contradicting the first part (or my interpretation of it, at least). Some people definitely find me rude, usually from older generations. I once had someone berate me for not removing my hat when I had entered a building (I forget where now). To this day, I still don't understand why this was an issue for them. I think I asked what they were on about, but they didn't seem to be able to explain
why it was rude, only reiterate that it was.
I also don't go to much effort to repair people's interpretations of my actions. For instance in a post office a few years ago, I was at a desk to fill out some form or another, and the desk had a bunch of pens all connected to it with string. They were pretty messily arranged, so I just picked up a pen in string-range of my form and started filling it out. The man next to me started going on like 'oh, don't worry about me' as people do when they want to make others feel guilty or something. I had no idea what he was talking about, and offered a sort of vaguely interested 'huh?' to which he responded by pointing out how the pen I was using was - ideally - meant to be the one for where he was standing. Not really giving a **** either way, I was like 'Oh. You can have it if you want.' but he kept on about how he was 'fine' and dramatically moved over about 1 ft to the next space (this was a desk for like 6 people, we were the only ones there). As much as he seemed to expect some sort of apology, I really just couldn't bring myself to care, and accepted his sarcasm as genuine. So, I'm pretty sure he didn't like me much.
One of my favourite memories from highschool following a similar theme was having been talking to my friends in mathematics class, and swearing in exclamation over something they said lead to the following exchange with the teacher:
me: '****!'
her: 'don't swear, thank you'
me: 'uh... god dammit!'
her: 'don't take the lord's name in vain either'
me: 'jes- uh...
****.'