Totally ethical if you ask me. Sometimes, there is not much work to do. All of my stuff is done, we are waiting for the client, etc. What would you have me do

Totally ethical if you ask me. Sometimes, there is not much work to do. All of my stuff is done, we are waiting for the client, etc. What would you have me do? Browse facebook or hacker news? Nope. I open a pdf or an epub and read it! ... that being said, I would feel wrong to read a physical book. I guess I feel as if I am expected to be at the computer for 8 hours a day.