2 of us working in a shop college goes to the stock room and a customer asks me to help her with an item. I walk the customer and item back to the till to pay and there is a lady in front of the till who should I of served first. I served the lady I had been dealing with but the other lady got all grumpy and said she was here first. I did say I was dealing with this lady before she even entered the shop but my college would be along in a second to serve her but she walked out.