I avoid people as much as I can for that very reason. If I have to be in their presence, I give myself a pep talk beforehand and remember that the chances of the encounter being negative are extremely high.
I remind myself that people are inconsiderate, egotistical and rude. I close my eyes so I can fully take in the moment BEFORE I have to interact with them. That's the moment I'm trying to return to at the end of the day.
It gives me a reference point and something to focus on throughout our interactions.
I want to be stimulated as little as possible so I don't bring those thoughts or energy back home with me.
This means that I have to be mindful of what I say and do. I see it as a way of protecting whatever sanity I have left, so I try very hard to stay in control of my actions and words.