As an employee I’ve felt like it’s hard in the past to take initiative and do things that aren’t immediately and clearly justifiable as strictly necessary work. Reading a book might or might not be useful but doing something boring but mandatory is certainly not slacking. With that said any time I tried to take more initiative and take more risks (while making a sincere effort to work on the thing that’s going to move the group/project forward) and then just accept correction if I make the wrong call, usually work was more enjoyable and I was more productive (by estimation of me, other coworkers, and my manager).