grocery shopping with my sister

I really enjoy grocery shopping with my sister because she seldom accompany to do it. Well, I can’t force her tho so I just let her do what she want. Grocery shopping with her is my way on getting a bonding moment with her. One time, when we were about to pay our things, we were really mad that the cashier was too slow. It happened that she don’t have any barcode scanner with her so she’s doing it manually. We were really pissed off that time because my sister and I were too hungry and planned to eat out. We can’t do anything about it and just let it be.