This, plus I don't think work is spread out/designated in a good way, in some cases. I sometimes feel bad when someone in another division is working so frantically when I'm waiting on a new assignment.
....I do want to get paid for a full day though, since being on "standby" is still something. Not "get paid less hours for doing less hours of work". I think everyone would be poor, by that measure (if not salaried).
As a freelancer, I can tell you that this is indeed an issue. Really hard to try to come up with 40 hours of real actual work that a. someone wants to pay you for and then b. find the energy to actually do all of it in those 40 hours.
You get paid, but it can make you irritable by lack of stimulation...
Trust me, lack of money makes you even more irritable. Read a book or something if you're bored.
Though taking a wider view, I do understand. These bullshit jobs people are describing are killing us. The idea that everyone should work is idiotic in my opinion.