The habit outlived every reason for it

Line them up in order, the reasons you gave. At the beginning it was fitting in, being included, not being the one left standing apart. Later it was stress, and there was always stress, so that one covered a great deal of ground. Then boredom. Then concentration. Then the reward at the end of a long day. Then eventually no reason at all, just the hour arriving and you standing up. Six different explanations. One unchanged behavior, running underneath all of them without a single interruption.

Now notice which part moved. The reasons rotated. The habit never did. Not once did a reason expire and take the behavior with it when it went. You stopped needing to fit in and it continued at exactly the same rate. The stressful years ended and it continued. A thing that survives the death of every cause it ever claimed was never being caused by any of them. Those reasons were not engines. They were paperwork, filed afterward, to make a constant look like a series of choices.

This is what a mind does with anything automatic. It watches you act, writes an explanation underneath, and writes it fast enough that the explanation feels like it came first. The reason arrives after the hand moves. That is not stupidity, it is standard equipment in every person alive, and it is how something runs for decades without ever being examined once. Each year handed you a fresh justification, tailored precisely to whatever your life happened to be that year. You were reading your own press releases.

So when a reason shows up now, and one will, you already know the test. Ask it where it was last year. A genuine cause has a history and can produce it. This one will not. It will be brand new, minted five seconds ago to fit the shape of today. Name it out loud and most of its weight falls off, because a reason like that only works while nobody is looking at it. Thank God for the clear head, then get on with your afternoon. Nothing is actually asking you for anything.