Baffling...

 Jacob and my niece, Maggie, both 5 years old, had their faces painted at day camp.  That evening I scrubbed Jacob's face to get everything off.  After bath time, my sister-in-law, Amy, and I sat on the couch with the kids.  I noticed that Maggie's face was clean, too.

Me:  I had a hard time getting all that paint off Jacob's face.  Did you really have to scrub Maggie?
Amy:  Oh, Maggie did you wash your face paint off?
Maggie:  When I got out of the shower, it was still on my face, so I got some more soap and washed it off.
Me:  (Pause.  Quizzical look.)  This is a phenomenon I have never experienced.

My boys' philosophy is that if it doesn't come off when the water sprays you, it was meant to stay.