For example if a friend let you down, absolute last minute with a rubbish excuse and they had been consistently flakey - to the point now where it actually upsets you.
I find it very difficult to say (not as blunt as this obviously) “your behaviour has upset me” because part of me just assumes they will get defensive and it will turn into a huge argument rather than them just acknowledging my hurt and maybe not continuing the behaviour (by maybe not agreeing to go to things they know they don’t want to or cancelling earlier or just not letting people down)