I’m not a fashionable man, but I do know that at informal occasions, button-down shirts should be worn with the top two buttons unfastened. I admit that I did not know about or follow this rule until fairly recently in life, but it’s been drilled into me by enough people at this point that I’m pretty confident it’s…
source https://theinventory.com/forget-untuckables-tweener-buttons-are-the-real-inno-1836607706