Reducing is one of those things that took me forever to understand. Honestly, I still feel less than comfortable with reduce than I want to feel. You know that you really know a tool when you feel super comfortable reaching for it in a lot of situations.
A little while back I talked about a fun subject: comments as code smells. I received a fair amount of discussion and counter-viewpoints from readers on this topic. In fact, one fantastic reader Patrick Michaelsen went so far as to write a well-thought-out rebuttal.