My colleague/friend had a 40th birthday over the weekend. She had been excited about it for ages chatting about the party she was going to have. I presumed she was just inviting her 2 closest friends from work as they socialise often outside of work and didn’t really think much of it, but it transpires she’s invited half the staff. I work with her closely and have invited her to big events of my own, so I feel really hurt she hasn’t invited me. There are a couple of other people who she didn’t invite which I’m surprised about, and she did invite a lot of people who she openly talks badly about. I totally agree it’s up to her who she invites, but would I be unreasonable to basically pretend it never happened? Eg not ask her how it was etc.