Suffering in life is guaranteed. This idea is present in every major religion, and it’s obvious from everyday life. Outcomes are unequal. People are born with different abilities. Some people get worse treatment than others. Peterson’s daughter suffered from unexplained juvenile rheumatoid arthritis for decades, enduring years of chronic pain and risking amputation. There is little more to question the sanity and justice of the world than having an ill child. What kind of god would allow this to happen?
One response to this, as stated above, is to hate your god or the universe for these outcomes. Stretched to its extreme, this becomes hatred of existence, and the desire to destroy existence itself. When practiced, this leads to genocide and mass murders. Clearly this is evil, causing suffering in the name of suffering, and not the right response.
Another response, which only partially mitigates the suffering, is to acknowledge that limitation is critical to making existence meaningful. When Superman was created as a comic book character, he had infinite powers and could overcome any situation. This became boring. There was nothing for him to struggle against, so he couldn’t be admirable; no lesson for him to learn, so he couldn’t grow. In response, the writers had to make him weak to kryptonite to make his stories interesting.
Peterson could have wished for her daughter to have an indestructible metal skeleton, or an inhumanly high threshold to pain. But then her daughter would be changed to a different person, even a monster. What can be loved about a person can’t be separated from their limitations.
There are also coping mechanisms for dealing with suffering. Promise yourself that you’ll only worry about a problem at a specific time of day (not at night, or else you can’t sleep) then promise not to think about the problem outside these scheduled times. This conserves your strength and allows you to deal with the rest of life, which doesn’t care what problems you’re facing.
Finally, notice little bits of goodness that make existence tolerable, even justifiable. See the girl splash happily into a puddle with her rain boots. Enjoy a particularly good coffee or book or conversation. Pet a cat when you run into one.