I really like the question "how do you criticize people" with the followup "criticize me". At least, it makes me _think_. However, I'm also a tad on the fence: is criticizing people a thing I want people to do anyway? I think you're getting at the question of how to provide constructive criticism but it seems, ironically, like a destructive way to ask it. "How do you criticize people?" Well I don't criticize people, but here is how I offer helpful constructive feedback when I think it will be beneficial. Feedback and criticism are not the same thing, just look at the definitions.

As for feedback on your screen protector question: I think you might overvalue what it tells you about a person's habits. It seems like the kind of question Sherlock might ask someone and then deduce many things-- but in reality there are too many spurious connections. Why not ask directly how they approach things that require the utmost care?