I wonder how much size and body shape play into it. My maroon is head and tails bigger than my perc (and then some, probably). Interacts more with my yellow tang than anything else (they're just about the same size but even with the yellow she's more liked to be pushed around than to push around). So far she's the last addition to the tank, but I'm just about to buy my White Cheek so we'll see what happens then!
I put my fingers in the tank last night as I was getting ready to feed the tank and my maroon actually came over and "nipped" at my finger. Not in a "I want to hurt you" sort of way, more in a "hey is that food I smell" sort of way. It was pretty cute. My littler fish do that all the time but this was the first time that my maroon had gotten so close to my hand. Makes me want to find something to hand feed her!