I have a third reason. Abstraction, or code de-duplication, if done right, ends up making code easier to reason about. The paper that made me rethink everythi

I have a third reason. Abstraction, or code de-duplication, if done right, ends up making code easier to reason about. The paper that made me rethink everything I knew is http://www.mpi-sws.org/~dreyer/tor/papers/wadler.pdf http://www.mpi-sws.org/~dreyer/tor/papers/wadler.pdf and explains this wonderfully.