I agree with you. People need purpose. Ever owned a Border Collie and spent a couple days without giving it something to do? It's bad for the dog and dangerous to your home.

So yeah, even if no one ever really enjoying being a gas station attendant, getting up and going to a job to earn money and pay rent gives people a sense of purpose. And UBI definitely risks robbing people of that purpose. The alternatives to UBI soon though might be creating fake jobs or letting people starve.