It's simple, If I don't indent properly - I don't get to run my code in python.
Yes, I know I can make my code look cleaner in Ruby, but I'm lazy. Call me shallow, but sometimes not having to type in blocks and "end" is kind of nice because of the inherent indentation constraint. And that indentation makes it easier to find lexical scope hierarchy easily too (at least for me). YMMV :-)