I once had one of those old fashioned Walkman music players.
It was bright yellow, had "Sports" written on the side and it played those tapes that come in large rectangular cartridges.
It was temperamental if I took it on a plane. The 'Sports' housing was waterproof and it somehow depressurised so that the tape wouldn't play until it had been opened again after landing, like a fresh pot of jam.
I stopped using it ages ago, but then once found it whilst tidying some stuff away. I casually flipped it on and ba-blam, a little blast of an old tune that instantly took me back to the exact beach where I'd last been listening to it. Like the little scene had been caught in another form of pressure bubble. It was one of those moments of quick joy, vivid recollection and was totally unexpected.
That's why I sometimes use old tickets and receipts as bookmarks when I'm reading.
Yesterday, I innocently restarted a book I'd put down for a while. One I'd taken for granted and half thought I'd finished except I couldn't remember the ending.
There was a prominent tell-tale red 'Priority Handling baggage tag' used as bookmarker part way through, which allowed me to pick up the thread, but then 20 minutes later a similar time-capsule from the past fluttered to the ground reminding me of languid times in faraway mountains.
I enjoy 'now', but sometimes a quick excuse for 'then' can be good.