Costco review: cashier: jennifer k.

I have been an executive member for a few years. I met an absolutely impolite cashier (according to the receipt, her name is jennifer k.) on the morning (09:19 am) of 09/19/2015 at the costco in san francisco, ca. after I swiped my credit card to pay for my items. she held onto my membership card. below are the dialogue between the cashier and i. cashier: "is this your card?" me: "yes." cashier: (she pointed to the picture on the back of the card) "give me your id. I need to check!" me: "why? do you check every customer?" cashier: "yes." me: "you did not check the id of the customer in front of me." (then I passed my id to her. she compared the membership card and my id and then returned my id back to me. after checking my id the receipt came out but she held my receipt in her hand and my membership card and turned to face another side. she then proceeded to help the next costumer while I waited for her to return my membership card and receipt. this lasted about a few minutes.) me: "please give me back my membership card and my receipt." (there was a packing boy helping and standing next to her. he asked her, "have you returned her receipt"? she did not answer.) cashier : "sir! sir! sir!." (a man was talking on the phone not far away from the cashier counter and responded, "yes, yes, hold on.") me: "what is your name? (her employee card was facing herself and she refused to tell me her name.) me:"what's your name? I have already paid for my stuff. you cannot hold onto my receipt."cashier :"sir! sir! sir!"man:"yes, yes, wait!"a few minutes later the man came over. the cashier gave him my membership card and receipt and told him to explain why she had to check my id. he ushered me to the side. man:"did she check your credit card and match it to your membership card?"me:"no."man:"you should have checked your credit card instead of your id. I am very sorry for the inconvenience. I will talk with her privately later." the man had not even given me a reason for why the cashier had to check my id. I was in a hurry so I left. I am very disappointed with the services that sf costco has provided! the attitude of the cashier was really bad. I don't understand why costco can accept impolite behavior like this. I come to the costco to support their business, but this employee there made me feel very unwelcome.