The Wrong Abstraction

I've been thinking about the consequences of the "wrong abstraction." My
RailsConf 2014 "all the little things" talk included a section where I
asserted:

duplication is far cheaper than the wrong abstraction

And in the summary, I went on to advise:

prefer duplication over the wrong abstraction

This small section of a much bigger talk invoked a surprisingly strong
reaction. A few folks suggested that I had lost my mind, but many more
expressed sentiments along the lines of