Problems with my comprehension

A couple of days ago, I got gas for my vehicle and I usually use my debit card but this time I used a gift card that I had. I parked near one of the gas pumps, looked at what number pump that I parked near and I went inside.

I handed the cashier the gift card and told her that I’d like to use it on pump number one. She asked me how much money was on it and I told her the amount. She also asked if I just wanted regular unleaded gas and I said yes. The cashier slid the card on her register and a few moments later she told me that the gift card was empty. I was a little confused since I thought that there was money on it. I told her that there should be money on it and she said that she had just used it for the pump that I requested. I said, "oh okay. Sorry." Then I went outside and pumped the gas and all was well. I just hate when I don’t understand something! It makes me feel so dumb!

Yesterday, I went shopping at a small store not far from where I live. At the register, I showed my rewards card so the cashier could scan it. Then I thought that she asked me for my zip code, so I said what it was. She looked at me strange and said that she hadn't asked me for my zip code. I just waited for her to finish the sale so that I could leave. I have no clue what she said to me, but to me it sounded like, "what is your zip code?" I hate that sometimes I don't understand things.