You should attend to your own business. ✬

You should go about your business. ✬

This business plan of yours seems almost too optimistic. All I can say is I hope it's more than just wishful thinking. ✬

It's none of your business. ✬

Mind your own business! ✬

You have no business doing it. ✬

Business is so slow these days. ✬

I canceled my appointment because of urgent business. ✬

Urgent business prevented him from coming. ✬

Business is business. ✬