What is the purpose of suffering if there is one? Causality proponents state that suffering is the result of our past sins or evils (greed, arrogance, and self love). We sow what we plant. The fruit or thorn appears in the future, often appearing in the next lifetime. This is why it is so difficult to understand why we suffer.
Suffering is not a stigma. It does not make one an evil person. Some would look at suffering and believe that it is justified and deserved. But they are totally in error. We all have sinned since we are all selfish creatures; we all will suffer to some extent. Suffering serves to remind us that we can plant good seeds today that we can harvest as joy in the future. When suffering or inconveniences occur, it is certainly difficult to accept what is unacceptable; but accept it joyously, and with good thoughts. This will bring forth joy in the future. Realize that our sufferings are temporary; joy can be everlasting if we can eliminate the evils in our minds.