Please dont sweat the small stuff
I am happy that I finished Chapter 7 of SJT today. It was a mammoth chapter. It involved a lot of thinking and I am a stronger programmer for having made it.
That being said, I really needed to fight my addiction to perfection. On a hard exercise, I took the liberty of stringing together several prelude functions without (a) learning how they worked or (b) rewriting them myself.
Also, my solutions may not be the most efficient.
But you know what? I'm done with the chapter and I'm better.
If I really wanted to be anal, I would have to rebuild the hardware I'm on for max speed. And then recompile ghc with all the right compiler flags, etc, etc.
DONT SWEAT THE SMALL STUFF!