When I was a newspaper travel editor, I came to the conclusion that something about coming into possession of an eTicket caused people to forget the rules of civilized behavior, consumed by the conviction that “the rules can’t possibly apply to me.”

“I don’t need to stand in that line. I don’t need to take off my shoes or open my computer in the security queue. I don’t have to make sure my carry-on fits. I don’t have to wait until my row is called. I am The Exceptional One.”

Then I began to think that Exceptional One disease was a little more widespread. I’m thinking maybe some people suffer an attack every time they go out in public.

Especially when they’re grocery shopping.

Or maybe it was just that, when I visited Costco last Saturday I was trying to move quickly. Or possibly it was that I was kind of cranky before I got there.

But, please, Costco shoppers, what is it you don’t understand about there being other people on the planet with an equal right to space, locomotion and a timely parking place?

So can we go over those supermarket ground rules again?

1. When you are in a public place, particularly a place of shopping, and you are standing still, you are in someone’s way. If a glance around confirms that there’s someone behind you with a sour look and a stopped-dead shopping cart, perhaps you could move on or get out of traffic?

2. Consider this life-changing concept: If your cart is on the LEFT side of the aisle, and you are on the RIGHT side, contemplating the relative merits of chunky peanut butter vs. smooth, could it be you’re blocking the entire aisle? What would happen if you — oh, I don’t know — kept your cart in front of you, so someone could get by?

3. Quick question: Having fought your way into a crowded store why is it surprising to you that there are people needing to share your space. What do you mean, “Oh! I didn’t see you there.” When you are shopping you must remain alert to the Disturbance in the Force created by a nearby sentient being, or the Death Rays being emitted from their eyes.

4. When you approach the checkout stand, how would it be if you — again, just a suggestion — gather your credit card, your coupons or — God forbid — your checkbook before they’re needed? And how about taking a minute somewhere uncrowded to ask yourself what you forgot so you don’t have to leave us all waiting in line while you run back for the cat treats. If you’re prone to this behavior, would you just shoot me a text when you’re heading for the store, because I seem to have a magnet-like attraction for the line you’re going to be in.

5. After shopping, in the parking lot, try this: unload the groceries, dump the cart and then, well, go away. Please don’t clean your purse, touch up your makeup or have an argument with the kids while your glowing brake light provokes a flutter in the hearts of the hopefuls coveting your parking space. It makes us want to go all Tawanda! on you. (Kathy Bates in “Fried Green Tomatoes,” “I’m older and I’ve got more insurance.”)

I know this is the kind of blog that can come off as all about me. But it’s precisely all-about-me-ism that’s the problem, I think.

Or maybe the problem is I went to Costco on a cranky Saturday.