It takes you all night to do what you used to do all night. Your kids start to beat you in your best sport. Then they find excuses to avoid playing with you. You need more time outs. You're always chosen to be the designated driver.
Professional athletes seem to look younger and younger.
So do policemen. You are shocked at the youths in military uniforms that you see. No one cares anymore about what you did in High School. You realize your father was right when he said it's as easy to fall in love with a rich girl as a poor one. You're smart enough not to take out all the garbage in one trip.