My son works in the US for one of the large auto parts chains. They have a metric where employees are constantly being measured as to their proficiency based on sales as they have to log into the register for each sale. The minimum is 40%, but his store manager goes by 50%. If an employee goes below 50% proficiency in a week, they will be written up. Two write-ups in a four week period, and the employee risks losing their job. (In an area where all businesses are understaffed and desperate for work, but hey, it's a company metric.)
A good example is, if you buy only wiper blades but not wiper fluid after the employee suggests it, then you are directed to the self-checkout. However, the self-checkout does not take cash. He had a day this week where four people bought wiper blades, refused the wiper fluid, and couldn't use the self-checkout as they had cash. In one shift, his proficiency dropped to 20% because of circumstances beyond his control.
The last time his proficiency dropped below 50% was a day three weeks ago where three people bought batteries, refused the conductive grease, replacement terminals, and terminal pads…then paid cash because they couldn't use the self-checkout as it doesn't take cash…
So, if you really want to screw the poor person behind the counter at a large US national auto parts chain, pay cash for wiper blades and batteries, and refuse the unnecessary accessories.
Fortunately, he has a new job and is leaving this one in a week.