There's a reason I'm an introvert. Whether we like it or not, difficult people are all around us. Yes the person who cut you off in traffic is a certain expletive, and yes that girl from high school you hated is another. However, I'm realizing in professional careers that there are just going to be difficult people that we (as civilized human beings) just must interact with.
3. Confront em, but only if you really really really have to - Sometimes you've got to just put expletives in their place. When that time comes be a cool, non-grudge holding, comeback goddess. No amount of negativity can harm you. With this in mind respond to difficult people directly and in absolute private. Tell them directly what it is they do that upsets you (only superficially) and ask them if there is anything you could do to help them change their perception of you. This puts the ball in their court and makes you look like a considerate grown-up, and not the vengeful child that's probably filling your mind with certain adjectives.
4. Get over it - You are an influential person. But some, very sad, people are just punks. No amount of grace or private confrontations can change change this person's very unfortunate personality. Don't let these type of people affect your work or your outlook on it. There are just always going to be jerks, and the best you can do is to avoid them at all costs.