[afarrell]

I think a lot of it is a lack of documentation. This has two effects.

1) People just get started and get used to not really understanding the interface they are working with. Who hasn't felt like they were playing whack-a-mole with CSS layout? This means lack of conceptual clarity fails isn't notable.

2) Nobody ends up noticing just how complex the rules are.

It was 9 years from when I started looking for a tutorial like http://book.mixu.net/css/ to when I actually found it. That is...really quite bad.