Father's Thanking Me??

So I mowed the lawn this afternoon.  It seems as though My Father mowed the front lawn but not the back lawn.  So I mowed the back lawn and, just because, I mowed the front lawn, too.

When I got done and went back inside, My Father says, "Good job!" and pats me on the shoulder.  Even though he has thanked me before, it's rare.  So to see him be this complimentary is ... strange.  And by the way, I didn't say anything to him.  It's shocking to see him thank me.  I'm still kind of spooked.