For me effortless cool comes from confidence, you have to be enough to be complete. No pretence, no showing-off, no people pleasing, just you as you are.
It's about doing what you feel is right even if it is against the norm or even against what others consider cool.
I think Ryan Gosling's character in Drive is effortlessly cool (in fact the whole film and the soundtrack are so cool...). That guy can make knitting look like the coolest thing ever, that's how effortlessly cool he is.
Is it me, or being a real human being makes you effortlessly cool? ;)
