We normally only have guns with us when camping or target shooting. Since we don't take them into stores or restaurants, I usually don't think about it one way or another. BUT - if a store / restaurant specifically advertised or posted NO GUNS, I would be hesitant about spending time there. Seems like most shooters choose "gun free zones" to do their dirty work in. The cowards want the most assurance possible that there will be no likely armed resistance. So I would choose to avoid those kind of places whenever possible.
OTOH, if I see some police cars in the parking lot of a business I am about to enter, I always feel a little twinge of relief, thinking that a bad guy would probably pick an easier target. And I think the same would be true, but to a lesser degree, in businesses known to "harbor" citizens who may well be armed. So no Starbucks for me!