He must have been proud

Today I walked into the restroom and I saw this guy, let's call him
Pedro, washing his hands at the sink, and he was looking into the
mirror and smiling at himself.
"Hi Pedro."
He glances at me.
"Hey."
I walk past him and go farther into the restroom to take care of my
business, and my nose tells me that Pedro must have made a poopie.
Then I understood what that self-congratulatory smile in the mirror
was all about.