I never saw tgif as meaning one hated their job either. I sort of think of it as carved out time for a separate purpose or when clients/students will not be calling and it is time to rest. I liken it to using a crate with one dog I had - she would get so tired and cranky (seriously she would get like an overtired toddler when she was a puppy) but literally could not rest until I had put her in her crate. Once in her crate - she immediately relaxed and fell right to sleep. It took all the pressure off of her (or that is how it seemed). She got better at being able to relax out of crate as she got older but it took until she was over a year old. She was one of the two dogs I have had who loved their crates. I left the crate out longer than usual because she would go in it herself - I did not shut her in it - but it was her safe spot.
She was a herding breed which I think had something to do with it.