Life-changing events are are easy to miss. This is especially true for the ones that come from nowhere. They don't fit into any of the compartments we make to hold the things that experience chucks at us, and so they just disappear. Only on reflection do these otherwise forgettable episodes take on the landmark status we remember them for.
An event like this happened to me recently. I walk regularly as part of a solution to a major occupational hazard of my profession, programming: long hours sitting in the same position wreaks havoc on a human body adapted over millions of years for regular daytime motion. These seeds of future chronic health crises start sprouting about middle age. Deliberate physical activity, including walking and cycling, was how I planned to avoid the worst of it.
It was on one of these walks, in early February 2023, that things got weird. Out of nowhere, I felt lighter than normal, especially on the left. It was a little like my step had an extra spring to it. The feeling wasn't exactly unpleasant, just strange. It worried me for a time, and then I decided to forget it. There was no box to dump this oddball thing into, so I did my best to Marie Kondo it right out of my life.