[srd]

I believe your main issue with understanding these things is that you're conflating (absence of) workload and boredom. Boredom stems from not having anything that engages a person in a positive way. For example, I can be drowning in work and still be bored out of my mind, even while working. The work being done is perceived as being tedious, rote and without positive emotional impact.

That being said, finding something "fun" to do for a bored person is no easy task. And sometimes nothing seems appealing to the bored person. You can try dragging them along, so that they'll get engaged in the process of doing something, but there's no guarantee that this will work. Sometimes people just need to be bored, I guess.