I was stuck behind someone jabbering on her mobile a couple of weeks ago. She was so busy talking, trying to load her shopping with one hand and attempting to keep her toddler in check he was completely oblivious to the fact she was holding up a queue of people. Then she had to add getting her purse out and sorting out her credit and loyalty cards to her multitasking adventures.
I nearly volunteered to pay her bill just to get get rid of her and the check out assistant was equally frustrated.