While I was grocery shopping this morning, a store employee sang along with the Stealers Wheel hit, "Stuck In The Middle With You," on the sound system. If you want to keep your job, that's probably as close as you can come to expressing your exasperation with customers.
"Clowns to the left of me, jokers to the right" is about the limit in most stores, I would think, of being able to express irritation on the job.
