A good example is legally required "security guards" for every apartment building but not defining the tasks or qualifications for the position. As a result there is an elderly person sitting at a desk in every building lobby, watching TV. The govt doesn't need to support these people as their benefits cost has been offloaded onto apartment owners.
This is exactly what the Federal Reserve does with its mandate for "full employment". When there aren't "enough" jobs, it loans out of a bunch of new money at low interest rates, for bankers to spend on outlandish bets - like say polluting the environment with electric scooters and hoping they'll turn into a recurring revenue stream.
"Full time employment" in 1950 was 40 hours per household. The definition was never adjusted when women entered the workforce en masse, so it's now 80+. With technological advancement, "full time work" should mean an individual works around 15 hours per week (with that "exempt" loophole closed). Economically, workers should have accumulated surplus and then demanded lower working hours regardless, but the previously described economic feedback loop saw that didn't happen, and instead the gains got siphoned upwards as housing and other economic rent.
That's the macro. At the micro level there are certainly motivations to create useless jobs. For one, the more people you manage/employ the more powerful you are, even if they're spinning idle. Also, adversarial entities can create jobs beneficial to their own self-interest while the overall situation remains nonproductive or even antiproductive (eg healthcare billing).