I don't think I have one.
I know people whom I get annoyed at for one reason or another, but nothing ever turns into a real "Internet Cut-Throat" argument.
I don't know of if there's anyone out there who would imagine me as an "Arch Nemesis", but I've never set out to make enemies. There's no point on the Internet.
If ever I do get mad at a person, or call them out on something, or even just be childish at someone, I never mean for it to be taken as something to work up a grudge about.
If ever I am mean/rude at someone, I generally forget that I was, in which case I would hope the person who I was rude against, would forget and forgive too.
If I don't forget, I generally feel stupid about it.