Mystification of cashiers

Sometimes I am mystified when people are mystified by my simple questions or requests. Two such incidents occurred recently.

Stefanie had a $15 gift certificate to Sprinkles Cupcakes that she scored free from the hotel she works at, so we treated ourselves during a lunch break recently. We each ordered a cupcake (milk chocolate for me, Bailey's for her), and she ordered two to take home for her boyfriend. I also ordered some milk, which put us over the $15. I told Stef I would just pay her the difference. I held out a $5 and asked the girl working the cash register if she could give me change. She looked at me as if I asked her to stick the $5 up her butt, light the end on fire and eat a cupcake at the same time. The blank look ensued, and she finally asked her co-worker, "Do we have change?" The co-worker's eyes got HUGE at the thought of exchanging my $5 bill for five $1 bills. More awkwardness ensued as these two brainiacs tried to do the math on this. Finally, Stefanie told me to just pay the girl the difference with the $5, less worry about the change issue. Oy vey.

The second incident occurred today at Jimmy John's. In lieu of a traditional baby gift, I wanted to buy a friend of mine a gift card since she loves their sandwiches, and it could be used on a night she didn't feel like cooking. I also wanted to buy myself lunch. I ask the counter girl if they sold gift cards, since I didn't see them shoved down my throat like I do at every other establishment. Blank look.
"Um, I don't know. No. Yes."
"Can I buy one?"
Blank look.
Turns to co-worker. "Do we sell gift cards?"
"Yeah we do," he says, almost exasperated by the question.
She shrugs. "I'll let you handle this."

While he's trying to figure out the gift card machine, I decide to give Smarty Sally a separate task.
"I do want to order a sandwich."
"Oh great," she says, eyes perking up at a word she knows.

So another guy starts making my sandwich while the Gift Card Guru is still working on my request for a $15 card. Smarty Sally decides to ring me up.
"That'll be $7.01."
"With the gift card?"
Blank look, furrowed brow.
"How much was your gift card?"
"$15."
Furrowed brow.
Gift Card Guru is able to do the math: "$22.01."

Sigh.