Whenever we get into an argument or a misunderstanding with someone, the spotlight in our head immediately dims anything that will prove us wrong and shine bright on the things that prove us right, no matter how small it is. It's so easy to feel like we're in the right because no one wants to be at fault, no one wants to realize that they've made a mistake - everyone wants to believe what they want to believe. Isn't delusion such a comfortable yet dangerous thing?
And the saddest part is that we are not evil people. We're just dumb and delusional and a little bit vulnerable and scared. So that when our conscience finally catches up, we are left with regret. However, I must say, regrets are good most of the time. The bitterness allows them to serve as a lesson and a reminder that people tend to use it as a stopper from repeating the same mistakes. At the same time, regret only follows guilt so when guilt surfaces a bit too late, regret just becomes dead weight - It's a burden and it's suffocating but you can't do anything but live with it.
Obviously I wrote this coming from a place of regret but thankfully I was lucky enough to get that redemption and all I can hope now is that my stupidity and ego won't win again and allow history to repeat.
So my unqualified advice to ya'all is that, if you care enough about something or someone, no matter how right you feel, just apologize. Say your peace but by the end of it, express your apology. Not for what you did but for putting the relationship, something you really care about, in jeopardy.