I love the chord changes in songs like this, Cretin Hop, I'm Against It, Gimme Gimme Shock Treatment, Carbona Not Glue, Commando, and Pinhead. They're so satisfying to play. Once you figure out the strumming pattern it's easier to keep up with their songs. They took mini breaks in strumming. It was like duh-[rest]-nuh-nuh-nuh-nuh-nuh-nuh. You can really get humming along once you get that down. Play only downstrokes and use barre chords NOT power chords like everyone thinks. Actually, for Cretin Hop and I'm Against It, he played the open chords at the top of the neck. Watch what Johnny does in this at 00:54.