Good point

The other day I was on a mini-bus with a 5-year old Egyptian girl sitting next to me.

"Are we friends?" she asked.
"I don't know, when do you consider someone your friend?" I said.
"Maybe when I like to play with them?"
"Could be. Or when you go over to their place or they visit you."
"Or when I dance with them? And want to hold their hand?"
"If that's the case you're definitely friends."
"Oh and when I don't bite them. Because you should never bite your friends, right?"
"Right."