One of my old school friends ruined my 21st birthday by calling a friend I'd made through work a "Pikey", a "dirty Gypsy", and continuing to drunkenly ask her to "get her fortune telling ball out".
It was the first night I'd had out in 18 months (I had a baby whom my parents couldn't be convinced to mind for a few hours... my work friend's mother babysat my daughter overnight so that I could enjoy my 21st), and it really opened up my eyes as to this particular old school friend. He lived in the posher part of the same town as my work friend, so obviously considered himself "better", or more superior to her... but really? He was just a jealous, nasty, dickhead of a snob.
Old work friend is still one of my closest friends almost 23 years later... my 21st was the last time I saw/spoke to the bellend who made her cry in the pub toilets.
Also my 21st. My parents, baby daughter and I were going to go out for a meal on the day itself to celebrate. My mother had been to a course the day before on body language and... actually, I forget what. 10 minutes before we were about to leave to celebrate my 21st, my mother started yelling about how my father and I were being disrespectful to her, our body language was this/that/the other, and she knew what we were really saying, because she'd spent (3) hours being taught about how to read it, blah, blah, blah.
We didn't go for dinner.
My parents still haven't acknowledged that I actually turned 21.
I spent the night feeling as though my own mother cared more about imagined slights (I was just trying to get my daughter ready at the time, so fuck knows what my mother imagined I was "saying about" her through body language), than she did about me. It took years, absolute years before I worked out that actually? My mother just couldn't stand that it was my event... my celebration... and not hers. She made herself the absolute center of attention on an evening when her only daughter should have been.
I've never told anyone either of those petty grudges of mine before, but I still harbour resentment over both. Work friend is lovely, ex-friend still (I'm told) an absolute bellend... and my mother? Well...!