I live in a state (Georgia) where a carry permit permits both open and concealed carry. I have a permit and I wouldn't dream of carrying openly. It's simply a way to attract attention to yourself and, in a commercial establishment, to raise suspicions as to what you're up to. I would imagine that walking into a convenience store at night with a gun strapped to your hip is likely to make the clerk nervous at a minimum and might cause a really dangerous unintended reaction.
As for the reaction of an anti-gun friend or relative, my thought is that the best way to make a convert is to take that person shooting. Until a few years ago I didn't own a gun and wouldn't dream of owning one. I wasn't exactly passionate about gun owners' rights (although it was never an issue that I gave a lot of thought or emotion to). Then, one day, a friend took me shooting and that first trip to the range was all it took for me to change my mind completely. Within a few months I'd made a convert out of my wife and shooting is now our shared hobby.