Yes, it's something you wouldn't want to say to anyone you don't know well. It's an expression of great frustration. Usually it's said, "You're pissing me off!" or "This is pissing me off!" You're aiming your frustration at someone or something. As an alternative, you can say, "This is really getting under my skin!" It's less vulgar. "She is really getting under my skin with all her complaining!" and "She is really pissing me off with all her complaining!" Basically both mean the same thing.

Poor taste depends on the beholder. The expression is at least very informal, slang. One risks giving offense if used among strangers. You might say "it upsets me" or "it makes me angry".

Yes it's, "a vulgarity" (which I like and use all the time) never to be used in formal situations, or in polite company. It means this is annoying me. This is pissing me off. That really pissed me off. I'm pissed off. But then, "I wish he would piss off" means I wish he would go away. And.............Piss off......means go away. Oh and piss is slang for urine. (oh pissing about/pissing around means procrastinating, or wasting time, or being silly.

That's the meaning of "piss of": vb (adverb) Slang 1. (tr; often passive) to annoy, irritate, or disappoint 2. (intr) Chiefly Brit to go away; depart, often used to dismiss a person It's better if u don't use with someone that u don't know very well. U do better use: It's annoying me You are annoying me

well, good question. I even didn`t notise that. Working on English? Well done you! You seem to use italki a lot Ariel? No? No offence, but Ariel? hahaha...