(Or at least, they are worse when you don't recognize most of the information being summarized.)
In a course I'm taking, I saw a graphic today that's supposed to summarize a nonlinear process and found myself anxious. There are five blocks and each block contains a list of two to five items. At this point in the course, I've learned about and practiced the skills for exactly one of these blocks. The others only serve to overwhelm me with Things I Should Do, or Things I Will Have To Remember Eventually.
I suspect this graphic would work better if it started at the highest level of abstraction and I filled it in myself as I worked through the course. That is: At first it's just the blocks. After each relevant module, I fill in another item or three in the appropriate block. But that's not how it works.
Beware of giving too much detail.