If someone tries to be offensive, I'll be amused, because that player may be off their game. I only care about game chat in so far as it might offer some insight into the mood of the other players - insult me all you like, I don't care.
As far as stress goes - yes, it's more tense when there's more money on the line. It gets easier with time - and it's much easier when you're not playing scared money (i.e. money you can't afford to lose). However, there's just general life lessons - if you made the right choice and got unlucky, that's life sometimes, just move on. Focus on where you are and where you go from there more than how you got there, because it's the things you can change (i.e. the future) that should be the focus. That focus helps reduce stress because you're not fixating on the past and the mistakes you made or that unlucky hand.