While I don't agree with the general snarkiness towards Haskell of the commenter you are replying to, being lazy by default could be seen as Haskell original mistake. It was interesting from a research point of view though.
What set Haskell apart is how it successfully limited side effect to the IO type and the introduction of type classes.
Laziness by default is definitely a bad design choice as far as I'm concerned. The drawbacks are not worth it.