Deja view?

"Supernatural" is one of those shows I always mean to watch more of, but due to its timeslot and the fact that more and more time passes and there are more and more episodes for me to catch up on, I suspect it's going to be one of those shows where I watch it on DVD years after it's over. For now, I've seen maybe a dozen episodes of the show across five seasons - and every time I randomly put on a repeat, as I did today with the morning TNT airing (season two's "Croatoan"), it's somehow always one I've already seen before.

I mentioned this on Twitter, and to a few friends, and all responded that this invariably happens to them with one show or another: they've only seen a small percentage of the episodes, and yet those are the only ones that ever turn up when they go looking for more.

So, three questions: 1)What show works that way for you? 2)Is there some kind of statistical theory that would explain how this happens? 3)Is/should there be a name for this specific phenomenon with TV shows?