Up here you need to have a CC permit to have a loaded gun in the car. But that's immaterial to your main question.
Also immaterial to your main question - but still worth mentioning - is the fact that it's pretty normal to look angry after a car full of kids rear ends you. Granted I wasn't there, but I don't think a gun would have done any good in that situation. If you do that's a little worrisome.
But back to your actual question. If you want an honest answer to the question "would people treat me differently if I had a gun on my hip", the answer is an unequivocal yes.
Some OC proponents might disagree with me, but open carrying a gun in a city makes you look like a fool. It may be within your rights in some states, and you might be the greatest guy in the world, but when most people see you they're going to think you're a fool at best, and they're going to treat you as such.
If you can afford a gun and the ammunition to get proficient with it, you can afford to go through the process of getting a concealed carry permit.
si vis pacem para bellum