Yes,working at McDonald's makes him smart. 
I currently work as a writer for my ex-game design teacher, with paid forum moderatorship and game studio interning coming up within the next few weeks, and I do PR for multiple companies on contract.
The "Mc" part of my name is a joke; my first job was at McDonalds, and they never technically fired me. Hence why I was "McJobless".
I guess the brain power required in order to understand that may be a bit more than you're capable of using.