We don’t know much about Kabbalah other than the disclaimer not to learn it before turning 40. It’s one of those cryptic things that’s never elaborated on, like when you’re a kid and notice the adults are talking about something interesting, but then they quickly clam up when they see the kids are listening.
Kabbalistic references sometimes just pop up out of nowhere. There are those words that show up after counting Sefirah (incidentally, that’s how they name Israeli seminaries; and yes, we’re so proud that your daughter is going to Tiferes V’Netzach next year). We also get the random paragraphs in Birkas Kohanim where you’re supposed to scan names with your eyes but not say them out loud. No explanation beyond that, just a terrifying warning from ArtScroll while you’re already keeping your eyes away from looking at the Kohanim.
The one Kabbalistic custom we all know is cutting nails over a garbage can or toilet. People on public transit should adopt this custom! (I’m sure Rebbe Shimon is proud that part of his legacy is proper cuticle hygiene.) The reason being is to prevent a pregnant woman from walking on your discarded nails and miscarrying. Oh, you have questions on how your lifelong habit of nail biting could hurt the continuity of the Jewish people? Sorry, we can’t go into it right now; you know… Kabbalah.
