I will do everything in my power to avoid the checkout line at the drugstore.

I will refill a prescription a month in advance in order to pay for my items at the pharmacy counter.

I will scan and rescan one item six times at the glitchy self-checkout machine without complaint.

The line at the drugstore changes you.

First, there's an issue of mismanaged expectations. Nobody anticipates a long wait at the front.  At the pharmacy, sure — that guy's rash demands answers. But at the main checkout, when you're holding only some floss and a pack of toilet paper, you expect a quick errand.

A fool's errand.

When you begin to realize it's taking a while, you question yourself. Why are you even buying this floss anyway? You're going to use it for two days and then forget forever.  But you need the toilet paper, badly. You've already gone through the Kleenex box. So you have to wait in the line.

And wait.

And wait some more.

The store can seem completely empty while you're shopping, but the line is always full. There could be only three people ahead of you, but it counts as full because there's only one person working the registers.

It's like an optical illusion of service.

Every drugstore has a giant counter of five or six registers at checkout, but have you ever seen more than one cashier working at them?

OK, two cashiers maybe, but the second appears only after the first makes several pleas over the intercom, and the new one always seems low-key angry about it.

So you've got a pinch-hitter cashier who's mad she got interrupted from staring down teens in the condom section, and the original cashier who's mad she had to call twice, and a line of irritated customers wondering why she took so long, and why the guy in front of them is taking so long, and before you know it, the whole place is rife with low-simmering resentment.

As a child of divorce, I both hate it and feel very at home.

I was really sweating it last time because I intended to commit a cardinal sin.

I wanted to use coupons.

Gotta love those sweet, sweet rewards.

People complain about the long receipts, but come on. Those receipts contain coupons for cash back.

I wish more stores would inconveniently give me money.

That day, I needed razor blade refills and deodorant, and I was going to use a coupon for the razors to get cash back to use on the deodorant, which happened to have an in-store discount as well.  It was the kind of convoluted coupon shenanigans I knew would paint a target on my back in rewards-bucks red.

"I'd like to buy this stuff in two separate transactions, please," I said at the register.

Someone behind me gave a loud sigh.

But the deodorant discount didn't show up. I pointed out the omission to the clerk.

"That offer doesn't apply to the twin packs," she said.

"Really? Because it said on the shelf any Dove product more than eight dollars qualified."

"Then that deal is expired."

It seemed like she was making up reasons. I was having an internal battle between my people-pleasing tendencies and the hardening effect of being in the line.

"Would you mind checking?"

She called for a manager. I couldn't turn around to see if anyone was coming because I was too afraid to face my fellow customers' wrath. But I could hear them.

"All this holdup for one person?" one griped.

Mercifully, the manager arrived quickly. She tried it again on the register and shrugged to her colleague. "If it's listed, you have to give it to her." Then she looked at me. "Can you show me?"

Did she know what she was asking me?  The line would kill me for this.

I practically ran to the aisle. I showed her the discount posting, clearly valid and applicable, so I returned victorious.

"OK, with the two offers combined, you saved four dollars today."

"That's it?" said the voice behind me.

"Great, thank you," I said to the clerk.  "I appreciate the trouble, and sorry for the wai —" I'd turned to apologize to the line, expecting a pileup of angry customers, but trailed off when I saw there was only one: a little old lady scowling at me.

"I'll say. You took forever!"

I was shocked that all that huffing and puffing had come from this tiny person. In any other context, you'd want to help her across the street.  Now I was backing away slowly.

On my way out, I did overhear what she was doing at checkout.

She was returning a tube of toothpaste.

Look for Lisa and Francesca's new humor collection, "I Need a Lifeguard Everywhere But the Pool," and Lisa's new Rosato & DiNunzio novel, "Exposed," and domestic thriller, "One Perfect Lie," in stores now.  Francesca@francescaserritella.com.