I don't know: if we really wanted to be 'strict' every integer operation should return a Maybe due to possible overflow, every IO operation also. That's a lot

I don't know: if we really wanted to be 'strict' every integer operation should return a Maybe due to possible overflow, every IO operation also. That's a lot of possible error to handle! I don't like exception's invisible flow but I think that they are good for 'should never happen' errors.