The meaning of jokes

Haha, I got it, too, but it wasn't from my boyfriend.

I think it's fun to hit you first and then you cry to coax you. You think it will be good for you in the future. Who knows, hitting you again is just a joke.

This is what I found in the novel about this joke:

You and I are lonely in pairs.

Can sadness last so long?

The world may be different.

It will become a carefree time that belongs to us only.

Another joke is similar: if there is an afterlife, let's be right mice, love each other stupidly, live dull, snuggle up purely, and be silly together. When the mountain is closed by snow and ice, we will nest in the warm haystack, I will hold you and feed you rat poison.

The warm feeling is a little sad.