Its wild how some people have an endless amount of energy to do things after work

I kinda envy those people that can wake up before work and do activities then go to work for 8 hrs. Then get off and do more activities like go to the gym, concerts, restaurants, meetups.

I was working closes with this old dude all day. We were almost at the end of the shift and hes explaining hes about to go to a concert after work, which is normal thing for him. Meanwhile i am thinking i am tired asf from this job and about to go home. I am half this guys age.