I think the mindset shift is when you stop dealing with single instances of anything and begin to think about their groups, relationships, constructions, data f

I think the mindset shift is when you stop dealing with single instances of anything and begin to think about their groups, relationships, constructions, data flows.. functional programming (and immutability) allows you to (eventually) write things faster.. you have to play around a lot with lists of things before it starts to click in.