No, not the buttons or collars, they vary. What remains the same is the pocket that stays on the left. Yes, these days many shirts have pockets on both sides but since the beginning the pockets have always been located on the left side of shirts and not on right and here is the reason behind it…
It is way easier to use a pocket on the left from your right hand and therefore they are located on the left. But, if you are thinking what if a person is left-handed?
I can just say, ‘majority wins’ because most people are right-handed, therefore shirts have pockets on the left.
If you have kept something protective or hard like a coin or mobile in your pocket, it can save your heart from any harmful attack or strong penetration.