Sam2: I have to de-lurk myself to disagree with you on Rav Bar-Hayyim. The emphasis his machon shilo places on Yerushalmi over bavli is his own chiddush. I also have it on very good authority that some of his historical conclusions are without any evidence but I won’t argue that point since I haven’t researched them and am no longer entitled to badger my rebbeim about things like that.
Edit, just to have something on topic for a change
Halacha: Wear tefillin
Minhag: Rabbeinu Tam
Chumra: Gassos (or common sense given the state of judaica store peshutim)
Shtus: Your tefillin are passul because you don’t have “double-black” retzuos. (Reb Yid, take a shot of double black yourself, and calm down!)
Alternatively:
Halacha: Don’t eat or own chametz on Pesach
Minhag: Don’t eat Kitniyos
Chumra: Peanut oil.
Shtus: Sell your peanut oil keilim with the chametz.