I'm mid 40s and very guilty of throwing rock star shapes. I was doing it at 15 and I just default to still being like it now, without really thinking about it. Some go for the Bill Wyman thing which is great if it works for you but I still can't shake the Paul Simonon thing, despite not having actively listened to the Clash for years. I'm not saying it's right or wrong, but I guess as you get older you become more comfortable in your own skin.