The ticket stub keeps proof of entry without keeping what the occasion meant.

Objects are good at recording facts and poor at recording feeling. The stub confirms a date, a seat, a price, and none of that is the evening: not who you went with, not what was said on the walk home, not why you have kept a piece of card this long. The keepsake is a hook, and the thing it hangs on lives in you.

If a small object matters to you, write two lines about why and keep them with it. Not a full account, just enough to restore the occasion later. Otherwise the paper survives and the reason quietly does not.