One of the things that makes it harder to break up with a toxic friend is that when incidents are broken down into isolated events, they can look like "no big deal", and the friend is usually dismissive about them.

If they are late to everything, sometimes causing you great personal (and financial) inconvenience, they will make it look like you're being unnecessarily "strict" or they'll insert their own personal line in the sand - "You can't really call it being late when it was only 30 minutes". etc.

Taking a stand against their constant disrespectful behavior can often look like you're 'keeping score', but it's something we must do - if only so that the next time they dismiss what we say, we can point to all the other times it's happened.