I would put the unfortunate scoping design above mutable defaults on the list of things that confused me. Also, I really don't like the decision to make Python

I would put the unfortunate scoping design above mutable defaults on the list of things that confused me. Also, I really don't like the decision to make Python 2 disobey the system locale and use ascii as the default encoding. Lots of Python programs out there have broken i18n for no good reason because of that (nobody starts teaching python by telling you to use .decode('utf-8')/.encode('utf-8') when you pipe data, and by the time you realize what's wrong, you often already have code out there.)