What regrets do you have in your life?

I think regrets are no meaning.
Because we can never go back.
It's too late now for regret.
Of course I always reflect on about my past conduct by myself.
Reflecting on the errors in my history is important, because it makes me next step.

Yesterday, it was a special day for me.
My opinion might be changed 180 degrees.

It was ordinary morning. I and my boyfriend took a breakfast at cafe, as usual. And we talked each other as always.Suddenly, one man spoke to me.
"Excuse me, you must be Sasanabe-san?"
"You must be Niibo-kun?" I answered just seconds after.
He was co-worker when I was a college student.
In addition to, I liked him very much. But unfortunately, I was refused.
I met him after an interval of almost 15 years!
I was really surprised.
He said he came here accidentally because of his business.
He stayed other hotel, he was supposed to eat hotel's breakfast.
But he thought he came here all the way.
So he walked around, and then he entered the cafe near his hotel.
And he met me after interval 1 decade.
If he didn't change his mind, we probably never met each other.

Should I have gone out with him?
Should I have got married to him?
Who knows?