Senescence
I did not realize that aging was going to happen to me, personally.
1988 (age 14) Glasses to correct near-sightedness
2010 (age 36) Discovered teeth require maintenance
2014 (age 40) Found that sitting cross-legged for extended periods causes knee pain
2018 (age 44) Had several lipoma tumors surgically removed and first bifocals
2019 (age 45) Revive cycling workouts and am keenly aware of how much weaker I am, and how much slower improvement is
2021 (age 47) Tinnitus (post-COVID) is frequent enough to be noticeable, and make me aware of just how poor my hearing is