Time is a bastard.
You're born-brought into this world with what the Greeks called "tabula rasa," meaning a "clean slate." Then life starts happening. You acquire knowledge. You acquire experience. You acquire wisdom. Your world is starting to shape as you go into your teenage years. That's when you'll get your first glimpses of real problems: the girl who breaks your heart, getting cut from a team, or physically hurting yourself during an effort to prove yourself.
Then come your adult years. That's when the big life experiences start. A few things on that list include:divorce, the loss of someone close, financial ruin, a longtime physical ailment, losing a job, coming to the realization that you're mortal, seeing something traumatic, etc. But even if you've experienced some of these, you've also experienced the positives in life: finding true love, creating life, making good money, learning to take care of your body, getting a promotion, making the most out of life, giving back to the people around you, etc.
With everything experience you accumulate, both positive and negative, it shapes who you are. You'll know when you're at the point that nothing fazes you anymore-when you've seen it all even though you know you haven't seen it all. It's at that point you can face any situation with the mindset, "Screw it, let's take care of this."
Time is a bastard, and it has made me one.
Ranger Up Old Man's Club Time is a Bastard Shirt