I'm thinking of writing a friend off over a potential misunderstanding on my part
You don't think that's a bit unwarranted?
I'm tired of the disappointment.
Ending a friendship over something you have done is not right. If it was your fault, just tell your friend it was an accident and that you can both be better.
It's better than keeping them around another second. They are stupid and annoying.
Why are you blaming them for something that you have done? It is bad to end a friendship in such a way. You should talk to your friend before doing anything like this.