Inevitably, as we travel through life, we will encounter challenging people- be they family, friends, co-workers or strangers. It's not easy dealing with someone with a difficult personality especially those who push our buttons, because they often turn us into people we don't like. But I love a challenge and have always looked at troublesome people and situations as a spiritual game of sorts: can I turn that person or situation from a negative to a positive. I don't think I've ever failed.
The first thing you have to do is set aside your pre-judgements and know that coming from a loving heart everything is possible. Most people will eventually react in a positive way if you are kind and loving, but it can take time to wear them down, and it does take effort on your part. It's not easy to be unconditional when you are faced with hateful or disagreeable individuals, but the work will usually pay off in the end.
I remember working years ago as an actress for a murder mystery dinner theatre company at a restaurant where in addition to our acting duties we also served dinner. We had to share the kitchen with the serving staff of the restaurant and they were not too happy to share the space. At first, they were rude and unaccommodating, so I immediately made it my mission to win them over, and eventually did. It was actually quite simple really, and cost me nothing more than a nightly, friendly 'hello, how are you'. They didn't really respond at first, and most people would have just given up, but this is where my love of a challenge came in: I continued to engage them until they started to respond. I did this by going out of my way to say hello, commiserating with them about challenging customers, thanking them for sharing the space, and just being nice. It worked, and made things a lot more pleasant. I did the same thing with some women in an office where I was temping. After a while they were going out of their way to be nice to me.
There are other ways to diffuse negative people and situations without ever coming in contact with them. Affirmations and visualization are both great ways of changing things around. You can do this by affirming harmony in all your relationships, or visualizing white light, or love, or whatever you find appropriate surrounding the person you are having trouble with. This has also worked for me on many occasions.
It really doesn't take much, just a little persistence and you can win over pretty much anyone. However, if for some reason they don't respond regardless of your efforts, then let go and detach, but refuse to stoop to their level of negativity.