To understand the nesting you have to evaluate the functions in the opposite order than you're reading them:

exclaim capitalize doubleSay

Sure, some of us has spent 20 years doing this so it's easy, but you can't deny that this is far nicer to read:

doubleSay capitalize exclaim

I'm a big fan of Fluent Interfaces, so I use this construct fairly often:

"hello".doubleSay().capitalize().exclaim()