I'm going to go off on a manager who isn't doing his job
Can't you find a better way to talk to him about it?
He's such a poor excuse for a manger. He's as bad as the worst of my ex-girlfriends.
You shouldn't go off on people. They can become angry and violent. Talking to someone calmly about their job improvements is a better idea.
I'm going to go off on him. I can't wait to do it.
Going off on a manager is not the best idea, especially if he is above you. You could try talking to him or whoever is above him about him work being subpar.