I just swallow my frustration. I have to deal with a number of people that frustrate, irritate, and would be the last people I'd invite to my birthday parties... but I just learned that it's not fair to anyone to have my attitude towards people being filtered through my own opinion of them... They might be very nice people, I just don't like them (I don't like a lot of people, so I guess practice makes perfect). I've also learned that being nice, and courteous to everyone even when though in your mind you are breaking there legs and punching their face, just because it's better you suffer for the brief interaction with them, than you voice your opinion, piss them (and others) off, and then make every interaction awkward.
One case is that I really don't one guy, but I've always been nice to him, then one day I needed something, and he must have overheard me, because he got me exactly what I needed without me asking. I never expected it, and he was happy to give it to me. Boom, he just earned 3 points in my book

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I dunno, I just always try treat people appropriately. I have friends were I'm harsh to, because that's when they produce their best work, and friends that need encouragement. And I figure, just understand why people are being stressed, understand their point of view, and then just work around that? Just always remain objective about everything. I refuse myself from passing my judgment of a person through my opinion of them, because if I did, I'd be a very mean and nasty person to everyone.