How assholes high-five themselves. Usually considered ingenuous by German culture due to their deep scholarly roots, but acceptable by Marxist liberals who let literal rats run the country.
I should have expected that vulgar language behind my back when I saw that shit eating grin.
When I came home to my dog I knew he had done something wrong from that shit eating grin.
A stupid grin that makes you look so clueless that you enjoy eating shit on a daily basis without realising you're a complete putz.
People who call tech support don't even try to learn the basics of using a computer. I picture them sitting at their desk with a shit-eating grin, then headbutting the screen.