For me its when my family flew in for my graduation and they also decided to meet my sister's in-laws. After graduation we were supposed to go to a restaurant. The ceremony was supposed to last two hours but stretched to four and we were about to miss our reservation. My sister pressured me to leave even tho I didnt have a chance to take pictures with friends and such. I have mostly moved on but honestly a part of me still hates her for it.
Ouch yea... the in-laws aren't going anywhere...
I don't have that much to be bitter about but your story reminded me of something that happened to a good friend of mine. they have a complex, sorta fucked up relationship with their immediate family, and on their wedding night, they had booked the venue for the reception late into the night, and their whole immediate family just left at like 7 or 8 pm without even saying goodbye, doing any dancing or mingling, etc. Even random in laws, friends, etc. stayed longer than that.... Theres a lot more context with the sibling and stuff that I won't go into but it was just heartbreaking like wtf