When we are young, we may meet such a person who sacrifices a lot for us at all costs, but we tend to ignore it all.
In the end, he will leave our world with wounds all over his body. No matter it is us or him, in the end, we will get married, have children, and live an ordinary life like thousands of ordinary people in the world.
At this time, we suddenly recalled the feelings that person had given us when we were young. Maybe we had loved each other then.
It's just immaturity that causes our regrets.