why people laugh

Today a student said that his cancer came back and asked if he could finish the semester from the hospital.

Then I laughed.

As soon as I laughed I felt bad. I was laughing at the absurdity of the situation, not at him. It was one of those you-gotta-be-kidding-me-laughs. Plus, he had a weird smirk on his face when he told me.

I'm really not a bad person.