[maxxxxx]

"I went from being an accommodating person to an intense asshole "

I have gone through the same process. Maybe it's because I am getting old, meditation or I just don't care anymore, I have slowly learned what's really important to me. I am generally pretty accommodating but for some things I won't negotiate and just say "No" without any further explanation.

This seems to work reasonably well with most people.

I don't really know what I am trying to say but maybe it's to have your priorities figured out and be flexible with unimportant stuff but firm with important stuff. That is, stuff that's important to you, not somebody else.