Insecure job, very poor training, favoritism, poor pay, absolutely no contracts to guarantee your pay, no benefits, no standard procedures regarding tardiness/write-ups/call outs/etc, poor communication.
Employees would be fired or have their jobs threatened for things that other coworkers would get away with constantly. Managers picked their favorites and only ever tried to accommodate them. Management would rather cut your hours down to one partial shift a week than accommodate your otherwise spacious schedule.
It’s difficult to remain cheery in a customer service job when the company cares so little about you.