I may be a purist of the unlined collar and full traditional fit when it comes to my OCBDs, but beyond that I am not so particular. I have OCBDs with pockets, no pockets, flap pocket, patch pocket, gauntlet button, no gauntlet button etc... There is something to love about all these combinations, I am not that picky beyond the full fit and the unlined collar.
I must say however, there are two features which, while not being required, certainly put any shirt over the edge in my opinion. They are the locker loop and the back collar button. I love these two features on an OCBD. They are the cherry on top and bring the shirt to the next level. Thinking about why I love these two features so much, they aren't really that necessary, many wont notice either and many don't ever use the locker loop and may even forget that a back collar button is even there. Why do I love them so?
I think it is the utilitarian aspect which I love. One of my favorite things about this style that we love is the functionality. The real-worldness of it. You can do anything in an OCBD. Go out to dinner, clean the house, go to work, mow the yard. It is a truly practical, versatile shirt that is meant to be used. These two features push the shirt even farther in that direction, I think.
Adding elements to pieces which are for specific use and also which are visible to the viewer - this is putting heavy emphasis on action, use, utility. It is not just adornment. I love that. This is about living, life, use. Even when I don't use the locker loop, I still love that it is there. I always use the back collar button. Even when no one else sees it, I still love that it is there. Yes I love these for the aesthetic, beyond the utility. That doesn't invalidate the utility. That doesn't mean it isn't important. There are layers here. This utility has become part of the aesthetic, and it is not totally useless and without purpose. The locker loop is useful and the back collar button does keep the collar down and keep the collar from revealing your tie underneath in the back, which can happen on the rare occasion. It is loved for both the aesthetic and the utility.
Unfortunately, today the locker loop and back collar button are hard to find on a shirt. Often they are practically impossible to find off the rack on a shirt with an unlined collar. Whenever I have an OCBD custom made I always, without hesitation request both of these features. For me, these 2 features exemplify the most niche representations of what I love about this style and approach to dressing.