I was expecting you to actually say stuff you couldn't come back from, but all of those are recoverable in your 30s and 40s if you're a bit more flexible. It's never too late if you want those things, quite literally.
For most people, the common one is heart disease. Plaque buildup is irreversible. No amount of dieting, exercise, or pharmacology will reverse damage to your arteries. All you can do is prevent further damage, and yes, you will need drugs.
Yeah, I guess this was more my point, you don't ultimately control that much about your health (is my perspective at least), you either win the genetic lottery or not, play the hand you're dealt, enjoy life while it last, in the way you can, some of us can only enjoy it so much compared to the rest of you.