I try, whenever possible, to keep toxic people out of my life. I encourage others to do the same. For me, a rule of thumb is: if the negative things a person brings to your life far outweigh the positive the relationship is toxic.
Unfortunately, it is not always possible to avoid interactions with toxic people. The toxic individual in question might be your boss, your child's teacher, a coworker in the cubicle next to yours, your neighbor, etc. You can - and probably should - limit your interactions with these people. Still, it is simply not possible to avoid them altogether.
That's the situation I find myself in now with my husband's ex wife, who is also the mother of his five year old daughter. This woman is about as toxic as they come! (I won't get into specific details. There's no point in trashing her in a public forum. Neither does it seem particularly appropriate to air the stains on my dirty laundry in such a venue). My strong preference would be to avoid all dealings with this woman. While I do keep our contact to a (bare) minimum, there are still times when I have to engage with her (like when I pick up my stepdaughter for our weekend with her because my husband has to work late on Friday nights).
Interacting with this woman has an emotional and even physical impact on me. On days I have to meet her to pick up my stepdaughter my chest is so tight with anxiety that it aches from the time I wake up in the morning until the whole ordeal is over. When I first met her I tried to introduce myself and be friendly. She was not receptive. Initially, I thought she would become less hostile over time. About a year has passed since we first met; things have not changed much. I have to accept that she might never become less hostile towards me (and my husband).
The reality is that if my interactions with her are going to become less emotionally distressing for me it's not going to be because she becomes friendlier. I am going to have to look inside myself to find peace. But what am I looking for?
I once read that when we don't like a particular individual it is because we dislike the emotions we experience when we are in that person's presence. Something about the person evokes in us a negative emotional response; we interpret this response to mean that we do not like the individual who triggered it. Theoretically, however, our emotional reactions to people say more about us than they say about the people who trigger them.
Cher Huber, noted author and Zen teacher (http://cherihuber.com), goes one step further. She states that not only do we not like being in the presence of someone we do not like; we do not like ourselves when we are in that person's presence either!
I look to my experience with my husband's ex-wife to see if this fits; it does. When I'm in her presence I stop being myself. I become focused on not setting her off. Suddenly, I feel like I'm eleven years old again, trying to be invisible so as to avoid being targeted by the classroom bully.
Cheri Huber suggests that we can make it easier to be in the presence of a person we dislike by turning our attention inward and remaining focused on liking ourselves. I've given some thought as to how to go about doing this. I've decided that the next time I have to interact with my stepdaughter's mother I will be armed with some self-empowering mantras I can repeat to myself throughout the encounter. I'm hoping this will help me to stay in touch with my "real self." I also hope it will help me to reach some sort of peace with the situation as it is. While I have to interact with this woman I DO NOT have to allow it to make me miserable.