My entire childhood, my dad's huge thing was always just letting things go and avoiding instigation no matter what. I didn't believe until recently, during my junior year of college, that it was actually very possible to just take the high road and be the bigger person. I've been pushed and pushed again and with my experience, I strongly believe it is ALWAYS way less demanding to take the high road when you are in a rut. I know it is way easier said than done, but there are a few things to think about when you are almost at your breaking point that will help you just let things go. The sooner you let things go, the sooner you can move on.
"How people treat you is their karma; how you react is yours." -Wayne Dyer
I've learned that no matter how hard you try to be nice to people or to even just stay out of their way, certain people will always find a way to treat you poorly. That is their choice and it is also their problem. Your free will also provides you with the opportunity to make the choice to either stoop down to their level or to rise above it and react the proper way; or just don't react at all.
"Never sacrifice your class to get even with someone who has none. Let them have the gutter. You take the high road." -Unknown
Seeking revenge is tasteless. Obviously the person who is causing you problems has their own issues so let them keep those issues. By taking the high road, you are only showing that you are better than them, and chances are they are trying to prevent you from being so.
"The best revenge is to be unlike him who performed the injury." - Marcus Aurelius
Like I said, reacting is going to give them pleasure. By not reacting and not seeking revenge, you are actually probably going to bother them more. It's important to remember this when you're about to snap.
"Haters don’t really hate you, they hate themselves; because you’re a reflection of what they wish to be. " - Yaira N
I think one of the most important reasons you should always take the high road is because you should honestly feel bad for these people. I know personally that no matter how poorly a certain person has treated me, I have always still felt guilt for treating them poorly back. It's still malicious regardless and the only reason most people will be out to get you is because they lack self-confidence and they're probably jealous of you. This should also help you hold your tongue.
"Anger is an acid that can do more harm to the vessel in which it is stored than to anything on which it is poured." - Mark Twain
Lastly, although it is way easier said than done, you should never succumb to anger. Mark Twain couldn't have said it better, but you getting angry in response to someone treating you poorly could really do more harm than good. More often than not it will only fuel the fire and provide a reason for the person to treat you even worse. You shouldn't even give them this opportunity.
All in all, it will never be easy to avoid conflict because no matter where you go in life, you will always run into people who thrive on it, but you can always resist that negativity and you always should.