Obviously, there is a point where you cut ties. But no one is perfect, and everyone will cross your boundaries occasionally. You do not have to choose between "they're dead to me" and "do nothing about it." Rather, you can talk to them, understand that literally everyone does the occasional thing they regret, and evaluate the frequency, severity, and intentions behind the times they piss you off.

Which would be covered under the 100% rule I implement on myself.

"everyone will cross your boundaries occasionally."

Not if they know your boundaries as you know theirs (through clear communication) and there is a total abundance of respect there for each other they won't. Hence my best friend being my best friend since age 15...

If they can't or refuse to talk things through, then they're not being an adult and they're not engaging in concise, clear communication. Ergo, we're not compatible and I walk. With zero guilt, or regrets.

If you want to build something worthwhile with another person you're going to have to compromise - but not on everything. You and the other person have to figure out what you're each willing to compromise on. And also how to handle any mistakes that you each will make.

I spent most of my twenties compromising with partners and ending relationships because of patterned behaviours on the behalf of them. Mistakes are only made when you're careless about something and don't put the effort in any longer. Relationships, using a bandsaw in a metal shop resulting in self amputation and any other number of applicable comparisons. I'm at a point in my life where I'm financially kind of secure, emotionally and mentally very secure. If you're going to make me compromise any of the support systems and proactive coping mechanisms I've adapted, I'd rather just not bother and continue being happy what I'm doing tbh.