K: His attitude is so bad, I can't believe it! I will tell the manager.
A: Don't, Ken. That's none of your business. Or, do you want to start a fight?
K: Why not?
A: Forget it!

K: 他的态度好恶劣，真不敢相信！我要告诉经理。
A: 算了，肯恩。不关你的事。难道你想找碴吗？
K: 有何不可？
A: 算了吧！

重点解说：

★attitude「态度」He took a friendly [hostile] attitude to us.「他对我们采取友善 的[敌对的]态度。」

★ That's none of your business. = Mind your own business.这是非常强烈的用语，带有「不要多管闲事」的味道。另外也有This is my business!的说法。