I'm not so sure alcohol is to blame.There is a reason I don't drink anymore, I don't handle the rude very well, and someone with no manners open carrying around my friends/family in an inappropriate situation might just be misunderstood.
Since I don't know if that random person is legal or not, they obviously have something to 'Prove' and aren't socially adept enough to understand the situation is inappropriate, a clear head makes for accurate evaluation and if necessary, shooting.
You seem to have your mind made up about OC, and have little room for flexibility when it comes to other gun owners (hence the low ready at the shop door).
If I'm there (OC) at a restaurant with my family, and I catch you constantly giving me the stink eye and coonfingering at your hip, what am I suppose to think?
Without any other interaction with me, you've already judged me because of my method of carry. That ain't right.
You've a level of niggling and disapproving that my ego likes, but my superego fears.