Good Riddance/Green Day

I know nothing about punk rock, but I have opinions about it anyways. Too loud. Too confrontational. I was listening to this the other day though, and was surprised to learn it's by a group that falls under the punk rock banner, although apparently they are considered “pop punk”, which sounds much fluffier (and makes me think my musical tastes are too) than “post-punk,” “anarcho-punk,” "Hardcore punk" or “Oi!”.