I went through the same process as you. I think it's okay not to have hard and fast rules for every acceptable situation to leave off parentheses, it's more a judgement call based on the readability of the statement.

`Require` and `console.log` are perfect examples where leaving off the parentheses helps with clarity, same with the call to `createServer`. In your example I'd even argue that you could do the same with `res.end` too.