Leaving their shopping carts out in the middle of the parking lot, rather than taking the cart to those designated spots the store puts out. (9/10)

Below are some people's comments on that.

01. "Had to deal with this last night. B******e left the cart behind my car, with the freaking corral not 10ft away."

02. "Ah yes. The true litmus test for human decency." 

Source: Ask Reddit