I can't write a story about a character who doesn't and/or hasn't suffered a lot. Why? It's simple.
Anyone who hasn't suffered a ton views the world from a naive and sometimes even entitled viewpoint.
When you see a person who has been handed everything look at people who have struggled with confusion, wondering why they worked so hard to obtain something that they received so easily, it says something.
The same thing goes for how happy a person is. When someone who has been loved all their life by everyone around them sees someone who has been hated and despised try to get revenge on the world around them, that person who has lived in happiness is someone who merely doesn't understand. If the protagonist has suffered, then it makes everything all the more reasonable for them to relate with those others who have suffered and turned to despair.
Suffering doesn't just build character, it is character. A person is defined by their sufferings, and also by how they react to them. Does this person lose all hope from slight inconveniences? Do they stay silent while taking everything on their shoulders? Do they struggle and struggle just to obtain something as simple as survival?
The more a person has suffered, the more insignificant it seems when they are faced with smaller problems. Even huge issues and extremely stressful situations can become relaxing to someone who has experienced life or death situations.