Once you understand the internal state of those who are consistently late to things you no longer feel anger towards them.
The idea that it's because they're being 'selfish' is one of those boomer clock slave beliefs – Embarrassingly poor theory of mind.
My most uncharitable belief is that if you're chronically late to things, you're just a bad person.
And I mean I don't think it's possible to routinely be late to events/work/appointments *unless* you're just a selfish person with no concern for anyone else.