1) They look awesome on dudes. They just seem to sit right, which is often what we men struggle with most.
2) The 3/4 button down is killer. It just is. But please, always leave the top one undone.
3) They come in a variety of colours and fabric types. So you can get the same great, awesome-fitting shirt in a light weight cotton for the summer, say, in white, or a heavier blend for the off-seasons and winter, say, in a dark blue.
4) They look great paired up with a scarf and a collared shirt (as in this brilliant example via Uniqlo)
5) They look great on Mom too ; )