A somewhat more depressing take: "There comes a time in everyone's life when you look into the mirror and realize that what you see is all that you'll ever be. And you accept that fact - or you kill yourself. Or you stop looking into mirrors." (Babylon 5, quoted from memory, so probably not 100% correct)

As I'm nearing 30, still in the "I can be anything I want" phase, I wonder when this time will arrive. And whether it is true for everyone - maybe some people possess the ability to reinvent themselves no matter their age. But can you even do that without giving up some contentment?