Empire Records

Empire Records is an independent record shop managed by Joe (Anthony LaPaglia). The store is located in a fictional city in Delaware, and, like its employees, is eclectic and unique. The staff is very much a surrogate family, with Joe as the reluctant and perpetually exasperated but loveable father figure. When his young staff experience problems in their personal lives, he routinely reminds them they can seek him out for advice.
The film opens with store manager Joe allowing employee Lucas (Rory Cochrane) his first opportunity to close the store, an opportunity Lucas regards as an honour. While counting the day's receipts in Joe's office, Lucas snoops and discovers that Empire Records is about to be bought and converted into a branch of Music Town, a large national music store with many franchises. In an effort to keep the store independent, Lucas takes the day's cash receipts totaling $9,000 to a casino in Atlantic City in an attempt to quadruple it via gambling. Lucas believes this act will create enough money to allow Joe to save Empire Records. Though initially doubling the money, Lucas soon loses the entire amount in one bet on a dice table. Instead of going home he sleeps on his motorcycle outside the store, where he is found the following morning by opening manager A.J. (Johnny Whitworth) and fellow employee Mark (Ethan Embry). He confides in the pair about the previous night's events before riding away, seemingly for good. Joe arrives to help open the store and quickly receives phone calls from both the bank and the store owner, Mitchell Beck (Ben BodÃ©), regarding the previous night's missing deposit.
Joe is distracted from immediately dealing with this crisis due to a scheduled store event: Rex Manning (Maxwell Caulfield), a former 80's pop idol, is due to arrive at the store for an autograph session to promote his new album. The staff is unenthused by "Rex Manning Day", and ultimately many of the fans showing up to meet him are either older women or gay men. The employees secretly tease Rex behind his back about his fading career, and even his assistant Jane (Debi Mazar) later reveals her distaste for Rex's music.
Lucas returns after the store opens and Joe confronts him about the missing deposit. After telling him of his short misadventure, Lucas is asked to stay in the store until a plan is devised to recoup the lost $9,000. Joe explains that he had intended to use the money to invest and become part-owner of the store, which would allow him the opportunity of saving it from becoming a Music Town franchise. Next to arrive are cashiers Corey (Liv Tyler), an overachieving high school student, and her uninhibited best friend and co-worker Gina (RenÃ©e Zellweger), both of whom are informed of the situation. Soon thereafter arrives hostile employee Deb (Robin Tunney), who is in a particularly bad state of mind; she has survived an apparent suicide attempt and immediately shaves her head in the bathroom upon arriving at work. Deb's boyfriend Berko (Coyote Shivers) soon arrives as well.
The afternoon continues in a downward spiral. A young belligerent shoplifter who identifies himself only as "Warren Beatty" (Brendan Sexton III) is apprehended by Lucas and subsequently arrested, promising to return for revenge. Encouraged by Gina, Corey's school-girl crush on Rex is pushed to its limitsâmuch to the horror of her friends, including A.J., who is infatuated with her. This leads to the revelation that Corey is secretly using Amphetamines. After arguing with Corey, Gina has sex with Rex Manning, causing the rift between the two friends to intensify and Rex to get kicked out of the store by Joe. Deb takes Corey aside and advises her on the questionable choices she is making, choices which may have dire consequences on her bright future. In return, Corey holds a mock funeral for Deb and the whole store attends. Gina then apologizes to Corey. The pugnacious "Warren Beatty" keeps his word and returns to the store with a gun (loaded with blanks) to seek revenge. Lucas reveals that he was once a troubled youth much like "Warren" until he was taken in by Joe, who gave him a home and a job and helped him turn his life around. The staff surmises that "Warren" just needs a similar chance. Joe subsequently offers him a job at the store.
After the police leave, Lucas admits defeat, and suggests calling Mitchell. However, the employees, Joe, and Jane â who has since quit working for Rex â pool their resources to replace the missing money. Despite their best efforts, they are thousands short. Suddenly inspired, Mark runs out of the store, jumps in front of a news crew covering the holdup, and announces a late night benefit party to "Save the Empire". The store opens its doors and collects donations while selling food, drinks, and merchandise to raise the remaining money. They manage to raise just enough, which they offer to store owner Mitchell. Mitchell in turn offers to sell the store to Joe, admitting that Joe has always loved the place while he himself has always hated it. Joe agrees to become the new owner. Corey meets up with a dejected A.J on the roof and confesses that she does love him. He tells her he has decided to attend art school in Boston so he can be near her when she goes to Harvard. They then kiss.
In celebration of maintaining Empire Records' independence and their victory against "the man", the staff ends the long and eventful day with a dance party on the store's roof.

Question: What do the employees tease Rex Manning about behind his back?
Answer: his fading career