Realise how small your window of opportunity is to see yourself at peak fizeek.
Reminder that unless you get yourself in good shape in your twenties, you will die without having seen what you were physically capable of. Young men are bundles of raw potential, not in a directionless way, but in the sense that, if you do the right things in your twenties, read the right books, lift weights, you will embody a kind of spiritual excellence which uniquely belongs to you. But if you squander these years, waste your time as so many do, this is tantamount to spitting in Nature's face, and (if you are a believer of any sort) in the face of God.
I honestly can't hammer home enough that you have such a short period of time to realise this potential. Very few do, fewer each generation. I don't know what age you are user, but no matter which side of twenty you're on, you don't have the time you think you have. The body you've been given is a gift, maybe the greatest gift, because of what it is possible to manifest with (let's be honest) barely any effort at all. Three days at the gym a week, cardio on off days, eating right. That's all. And if you do that, alongside reading good books, you will embody what is, no exaggeration, the highest form of life possible, the life of a young male, at the apotheosis of his powers, strong in mind and body.
But if you waste these years, and most do, you will never see this, and you'll live knowing that, at the crucial moment, you clung to life's outskirts.
Read "The Love Song of J Alfred Prufrock" by TS Eliot
i have seen the moment of my greatness flicker
and i have seen the eternal footman hold my coat and snicker
and in short i was afraid
This is you, or will be. This is most of us. The moment of your greatness, of potential greatest, is a flicker, a mere instant, and the rest of life is a slow decline. And never to have seized your moment of greatness before start of this decline, I can't think of a more cursed fate.