-1(*inf) Downsides: 1. New way to make a Haskell expression that makes no semantic sense `length (1, 2)`, and it still evaluates. 2. New trick interview question that makes interviewers hated for being impractical. (Just like `join (*)`.) 3. Confuse hell out of beginners and practitioners alike. Upside: 1. One Canonical(tm) Functor instance for tuple, and pope's own claim that the other instance does not fit in our library. 2. More standard types that are Functor instances. 3. Easier to demonstrate that one can DO EVIL in Haskell too. ​-- Cheers Michal