[dontbenebby]

Just refuse to be exhausted. So if someone seems to be arguing and exhausting you, because they want to "misunderstand" (argue) just don't let them. Shut down the conversation until the next day or week. These are your business contacts, not your friends, and you are their superior. People don't like being told what to do, and if you let yourself be tone policed you'll get an ulcer. Speak in a diplomatic way, use a compliment sandwich, all that jazz -- you hand ammunition to an intelligent person wanting to pick apart your language.

Speak shortly and directly, you're aggressive and condescending, at best.

So be ready to call the bluff if someone is basically threatening to not like you -- lots of people don't like their boss... that's why it's work, that's why you get a paycheck, instead of all living in a house doing tye dye and bong hits between coding sessions.