There are a couple of Easter eggs on this page – ALL in the first panel. The bartender’s name is Mac and the mean-bad-grammar guy’s name is Charlie – both an homage to It’s Always Sunny in Philadelphia. The big guy at the end of the bar with the number 11 and Peterson on his jersey is an homage to Norm from Cheers and the 11 seasons the show ran on TV. And there’s a washed-up Soda Popinski from Punch-Out!! also hanging at the bar.
It’s always fun to throw stuff like that into the book. Sometimes it’s noticed; most of the times it’s not.