Most people see suffering in a completely negative light. And this is not just on the physical level, but the spiritual level also. For example, the Buddha’s Four Noble Truths are usually interpreted as a way to end suffering. In other words, there are no positive aspects to suffering.
I have a different take: I think suffering is one of the best impetuses for growth and learning. Here's a song my husband Arthur wrote about the value of suffering—he calls suffering "the guru."
Stop signs and stoplights are red because human perception is keenly attuned to the color red; our blood is colored red and our physical survival depends upon us being aware when we've hurt ourselves. Physical pain exists, at least in part, to draw our attention to the fact that we are ill or injured. Most of us resist physical pain; we reach for pills to make it go away; we see pain as an enemy. But when you look at it from the perspective of “suffering is the guru” you see that pain is our ally, it draws our attention to a problem that needs fixing. The pain is the motivator for us to stop a behavior that's hurting us, to go to the doctor, etc.
Problems of the mind don't have an obvious physical symptom like a bleeding wound or the pain of a burn. But the sufferings of ego-identity—pride, embarrassment, anxiety, regret, remorse, depression—are the analogues of physical pain. The suffering is pointing towards the problem, in the same way a pain in my mouth points to a problem with my gums/teeth and sends me to the dentist. The depression or anxiety is our ally, our teacher, our guru, pointing our attention to a sore in our mind that is in need of healing.