1.Whats the most infectious riff ever? 2. Which is the most recognisable rock song ?

by infectious i mean you just cant help but nod your head when it comes on-my choice is "Jumpin' jack flash". most recognisable song i mean one that EVERYONE has heard and you can go pretty much every where in the world and it'll be recognized even if the name is not known- here my choice is either "born to be wild" or "bad to the bone"....