Why do we suffer? Because it steers us toward enlightenment. Everything we think or do that is part of the unreality of ego will cause pain. If it weren’t for suffering, we would keep living in illusion. We have to suffer in order to wake up.
As we wake up, we think and do fewer egoic things, so we suffer less. This is why we tend to have less anger and worry as we get older. Of course, some people remain in illusion their entire lives so their negative emotions and suffering don’t diminish.
Why should anything cause us to suffer? Sure, notions of materialism and superiority might be wrong, but why should they cause us pain? Because our purpose is to find out who we are. All illusions get in the way of that, and suffering teaches us which things are illusions.
But why should we find ourselves? Why can’t we exist in comfortable illusions? What benefit does truth bring us? Truth brings peace. Illusions don’t because trying to exist in something unreal is an attempt at self-annihilation, and anything that opposes our very existence cannot be comfortable. We, being real, can exist only in what is real, i.e., truth. When we do this, we experience the natural bliss of being.