When I first got into guns, I didn't have a CCW (now I teach the course!). I carried open some, just to get the reactions. (can't see how you can conceal if you're naked, though).
This was very interesting, and surprising, actually. So I go to walmart. I don't get very far before they ask me to put the gun back in my car in the lot, fair enough, and they were polite - even apologetic. about it.
Then they told me why they did that and some other things that seem stupid at first. Did you know if you buy a gun there - after the background checks and all - you can't touch it? They bring a manager to carry it out to your car for you. The reason?
Some guy brought in a shotgun shell in his pocket, picked up a gun from their case and shot himself though the mouth, quite messy and it didn't help their business. Go figure.
Then I go to get an oil change at the Jiffy Lube. They're fine with it (want to see it and the cool laser etc, back in the bay where they don't usually allow customers), but one of the customers, a big dude, looked like not-low-life, really got into my face about it, asking about my permit like just seeing a gun really pissed him off royally. I told him I had one (didn't mention it was the 2nd amendment though), and he backed off - I REALLY don't look the part of even an undercover cop.
So, while waiting, I go next door to a quickie mart to get a hot dog. The Indian girl goes crazy with obvious fear, so I told her I wasn't there to rob the place, and in fact would protect her if someone else tried, and besides - ever seen a robbery done by a guy with a holster? So she's fine - no problem anymore. (I could understand her fear - they sell scales there that are only good for either selling crack or reloading, and I'd guess the former is most of their sales)
Later, I go to the liquor store, where I think I'm really going to get a reaction of the negative sort. Couldn't have been more wrong. OK, some of them have seen me a few times, no one said anything, so I asked them - they said "fine, we know you're not a crook, and it'll scare possible other ones, so please DO carry and do it open". Wow! That depleted my cash (I don't carry much, or much booze, but I do get the good expensive stuff) so I then went to the bank.
I almost always go in, as there are a lotta cute chicks in there, one of whom is my "personal banker" I'd like to be more "in touch" with that one than I am, if you get my meaning. So in I go, right past the sign that says "take off your hat so the cameras can see your face if you're going to rob us" (ridiculous). No reaction at all there either, so I ask the girls, and they said pretty much the same as the guys in the liquor store - please do carry, and open - we know you, and what would you do, steal your own money? (I'm a big fish in that small pond).
Just FWIW, those are for-real experiences. I note that a sunny disposition goes a long way towards "disarming" bad reactions - a smile will get you far (but not as far as a smile and a gun, as Al Capone used to quote). Where I live, most people know most other people, and I never get a bad reaction in the stores I frequent...they have the same attitude, they know they're in no danger from me. Rather the reverse.
I did once have a Barry Switser moment, though. I'm in the courthouse to pay taxes or some such, and while fishing around in my pocket for something, oops, there's a Taurus ultralight in Ti in there- .38 - post metal detector. I decided not to rat myself out and just walked back out through the same detector. I now have more Ti in my body than that anyway, due to a serious injury - jaw and part of skull...so I have an excuse to set detectors off anyway at this point. I recently had to go to another courthouse over the ex, and man, they made me empty my pockets - no pens, even no little notepad - take my belt off, and I flew through their detector too - I mentioned to one of the cops (I know the guy) that I should have brought my gun, since my head didn't set it off. He said "this only detects crap, not quality metal", and we had a laugh over it.
"An armed society is a polite one".