While it might seem logical that the complete avoidance of toxins is best for you, some toxins might actually be good for you.
This phenomenon is called hormesis. It refers to a situation in which a small dose of a toxin causes a beneficial effect, while a larger dose causes harm. While it's controversial exactly which toxins exhibit hormesis and to what degree, it definitely occurs in some cases, and some scientists believe that some level of hormesis occurs with most toxins.
For instance, kale, broccoli, and many other vegetables contain small amounts of toxins. It's thought that these foods are good for you not in spite of, but because of, the toxins that they contain. These tiny amounts of toxins stimulate your cells to produce substances that protect them. Then, when they encounter larger amounts of toxins, they're prepared to deal with them. Cells that have never encountered any toxins are left vulnerable. Hormesis may be one of the primary mechanisms by which plant foods benefit us.
I see hormesis as being important in our lives, as well. People who are sheltered, who never experience any type of adversity, may become fragile, or they may have trouble motivating themselves to do the things they want to do. Those who experience a few difficult situations become more resilient. I know more than a few people who claim that their difficult experiences made them who they are today. (Of course, extreme trauma can be very damaging; the benefits of hormesis occur only at low doses of a toxin.)
What difficult situations are you dealing with now? Can you see how they might benefit you in the long term?