no holds barred

This isn't necessarily always malicious: when I go to the coffee shop, I would like a frictionless interaction with the barista wherein I place my coffee order, it's rung up correctly, I pay them the requisite amount of money and receive my coffee shortly thereafter. It's fine if there's a little friction sometimes (the register is messed up, they're out of an ingredient for what I want) but, y'know, I'm also not gonna be thinking about that barista all day, and it doesn't make a real difference to me who's working so long as they can perform their barista duties adequately and not cause weird problems. This is normal: not every interaction is going to be special. Sometimes frictionlessness is the primary goal of the type of interaction you're having. No one goes to the store hoping the cashier will engage them in a deep and meaningful conversation, that would be a very weird thing to expect.

But sometimes it's people who are actively and intentionally trying to take advantage of your willingness to bend yourself into whatever shape they demand. They may even take a perverse delight in giving you contradictory instructions just to keep you off-balance, telling you that you did something wrong by doing X today, and that you should have done Y instead, then when you do Y, berate you for not having done X or Z. And the more you habitually make yourself small and inobtrusive, the more vulnerable you are to this kind of person's manipulative and abusive bullshit.

The best defense is to cultivate an attitude not of willful rudeness, but of unapologetic willingness to stick up for your needs and the standard expectations that should be extended to you under the social contract. The barista should make your coffee order correctly -- if it's wrong, you're entitled to go back, point out the problem, and ask for it to be remade the way you ordered it. That's part of the social contract of making an order at a coffee shop. They expect to be paid and treated with basic courtesy, you expect to receive the coffee you paid for, not something else. This can be done politely, there's no need to scream and swear and berate them, THAT would be uncalled for and rude. But asking for your coffee to be remade when you ordered a peppermint mocha and got a caramel frappuchino instead (or whatever) because they messed up, is a normal and expected amount of friction for you to insert into their workday in that circumstance. If you're in a romantic relationship, you're allowed to assert your needs for things like emotional support, physical affection, etc. and to leave the relationship if the other party isn't able or willing to meet your needs. You deserve to be treated with respect and care by your friends and associates.