The path to success can be derailed by clashes with difficult people, and even if the clash isn't disastrous, it can make your life very unpleasant. Everyone has a store of coping mechanisms that we resort to when we find ourselves in stressful situations. Difficult people force us to fall back on our coping mechanisms. Some of us placate, others confront. Some balk, others become aggressive. When these first-response tactics don't work, when a difficult person makes you tear your hair out in total frustration, you have to dig deeper into yourself and find a better strategy.
First of all, not every difficult person is the same. There are tyrants, curmudgeons, aggressors, the viciously competitive, and control freaks. A psychologist can outline how each beast might be tamed, but on a day-to-day basis, one can adopt a general approach that's the same. It's quite a simple strategy, actually, based on asking three questions.
1. Can I change the situation?
2. Do I have to put up with it instead?
3. Should I just walk away?