This reminds me of an Undercover Boss episode (I think for Cinnabon).

The COO had mandated no more than 30 seconds per customer so that the line kept moving.

When she went undercover, she realized that 30 seconds was barely enough time to ring up the customer, hand them their order and move on to the next customer. Great from an efficiency standpoint but terrible for customer relations as the cashier didn't even have time to say "Thank you for shopping with us!" or "How is your day going?" etc.

It's a good reminder that optimizing too much for one metric (e.g. line speed, short term profits etc) can lead to worse outcomes in the long term. On the flip side, a few extra minutes of time and effort from an employee can turn a "nice stay" into " we are customer FOR LIFE!"