Y'know, even when I open carry somewhere with lots of people and a history of OC'ers being asked to leave or being denied entry, I don't have even the slightest issue.
I OC'd briefly at the Christiana Mall, where OC'ers have been approached by security and told by the State cops to conceal "with their permission" which of course you should never do without a permit. Last time I was there I stopped for lunch at a place attached to the mall, then I walked in, said hi to my sister at her work, and then browsed B&N for a bit. It was as uneventful as it is everywhere else Ive carried.
I've OC'd at Costco on several occasions. Not one person has said a thing about my carrying, nor do I tend to get stares or bugeyed looks.
People don't freak out over my gun. People don't cause a scene (aside from my father) 99.99 percent of the time people don't say a word about the gun. That's just fine by me, since I'm not a big fan of socializing with strangers anyway. Hell one older lady at the beach thought I worked at the grocery store because I helped her find some pomegranate juce and grabbed it for her. On the rare occasion someone asks and I tell them I'm not an LEO or private security they don't go screaming ZOMG gun!
Supposedly "Pro-Gun" people constantly say things like "Oh, if you OC at X place the cops will be on you in a second!" and claim it'll be a huge problem. Just like those who claimed you can't OC in Delaware because it's a blue state, the naysayers keep getting proven wrong.
Attitude and appearance matter, as they always do in life. Don't dress like a thug and you won't be treated like one. Don't act like an attention whoring douchebag and bad attention isn't likely to find its way to you.*
Are there places where I have reservations about OC'ing? Oh sure, but you never know unless you try. You might just be pleasantly surprised, even in blue states. Try it!
*Or maybe it's just because I have "kind eyes" heh.