Some good things about suffering
It's necessary for its opposite.
If you never suffered, then you wouldn't experience happiness either because it would lose all meaning. One depends on the other in the same way that night and day depend on each other.
It encourages gratitude.
A person who's never experienced the suffering of a serious illness does not truly understand the value of being healthy. Suffering makes you appreciate things that others take for granted.
It brings lucidity about your values.
Suffering can make you realise what you care about most instead of being distracted by unimportant stuff. This is useful, since your time here is limited.
It motivates action.
The drive to end suffering is one of the most powerful there is, and can be used as fuel for constructive activities.
It encourages humility and compassion.
Suffering highlights how much we depend on others and how we could not flourish or even survive without them. And suffering connects you to others, because it's one of the few things all sentient beings have in common. "We're all on the same bus here, going who-the-fuck-knows-where."