Thing that make you go hmmmm.

[catchnrelease]

9. One possibility

When I go to Costco I normally just have a few items, and in those cases I use the self check out. I've noticed the people in the employee check outs usually have carts really full. So that may be the difference. Even the fastest most efficient checker can't get through a cart heaping with goods vs an individual* with 6-10 items at self serve.

On Sunday morning however, I just needed to pick up one pharmacy item and was probably the first person to check out of the store and I used a regular checker. The self serve registers at my store always have at least 2 employees attending them, sometimes more.

*Edited to add: It occurred to me after I posted that it depends on the individual at the self serve--if it takes someone 5 minutes to get their cards out of their wallet after they get to the scanner, or they don't know the process and stand there like a deer in the headlights....you're better off going to the Costco checkers who ARE very speedy.