So, what exactly is regret? It is probably that this feeling can be recalled, but it was already at a loss at the time; or it may be that life is full of regrets.
Even if you know that there are some things and some people, even if you try to change and save them, the result will still be the same.
It's fleeting, that's probably how it feels, so because you have to lose it eventually, you'd rather not have it.
Intention: Memories and nostalgia