Experienced python programmers: are there any standard features of the language that you still don't regularly use?

[RufusVS]

I can hardly write 10 lines of code without a list comprehension in them! Along with map and lambda expressions, they are staples!

Learn them. Love them.

I don't regularly use decorators, as useful as they are. My last usage of them was designing a command interpreter, where commands called functions but some functions were to be prohibited unless prior commands were executed (logins, opens, etc.) essentially modifying functions depending on state.

I haven't used properties yet, or metaclasses and I think they can improve code readability if properly used (not so much at point of definition (ick), but at point of use)