I have worked in fashion for many years and often stand on the shop floor contemplating this that and the answer to life, the universe and everything. Last week I was wearing one of my favorite shirts and it suddenly occurred to me that on high quality shirts there is a small loop sewn between the shoulder blades on the outside.
I have some really old shirts (don't ask why I don't throw them away) that have a button on the back of the collar just above the "locker loop". Sometime in the 1970's buttons began appearing on quality mens shirts on the plackets... the portion of the cuff towards the elbow that used to just remain open...
Yes clanad, I've noticed them too and use that sleeve button all the time. I just don't like to button up at the cuffs and usually turn them up so find 'that' button real handy as it does prevent the sleeve from flapping about all over the place.
It used to be quite common to lose the odd button from a shirt while wearing it or washing it. Nowadays a shirt will often come with a couple of spare buttons attached. But ever since they started doing this, I've never had a button come off a shirt. Curious.