Customers leaving their shopping carts two feet from the shopping cart receptacle = the American lack of motivation to complete projects (e.g. Barack Obama's failure to conclude his inauguration by ceremonially sacrificing George W. on the White House lawn, the Mercer Street exit).
Customers cleverly hiding items they no longer want, hoping no one blames them when I find all 15 on-hand Robinson Home whisks tucked under the basket weave place mats = the American bad habit of hiding bad things in seemingly good things (e.g. using the Spanish-American war as an excuse to colonize small island nations, hiding spinach in my younger brother's pizza when he was three).
Customers' tendency to describe books they want as, "That new book Oprah likes" = the American obsession with stardom (e.g. stick-on "soul patches" during the Apollo Ono rage, hanging out with tax collectors and loose women because Jesus did).
Customers who bring ten Danielle Steel books to my register and expect me to smile at them = McDonald's (e.g. McDonald's).