Confession: I am a serial muffin dissector.
This is what we refer to as a "food ritual". If you've even been in residential or inpatient treatment for an eating disorder, you will come to hate this terminology, because any person will come to hate anything that they hear SIX THOUSAND TIMES A DAY. To be fair, it is those counselors' jobs to kindly but firmly say things like, "See, what you're doing is a food ritual. In the real world, people don't tap their fork to their plate three times after they eat pizza."
The gist: almost everyone has a few little eating quirks. These are mostly habits they develop as little kids then grow out of: eating food on their plate in a clockwise fashion or eating foods by color (yellow first, then green, then brown. . . ). I don't know, things like that. But, as with pretty much everything in the world, people with eating disorders take this to an unhealthy extreme. They develop these rituals mostly because the anxiety of eating a "normal" amount of food and digesting it like a Real Person is suffocating when you've spent so much of your life doing the opposite of just that. So food rituals aren't just actions; they're systems, and they generally serve as a way to lessen anxiety by exerting familiar control over eating, to take the edge off of an incredibly uncomfortable situation.
They tend to make little sense, but it is extremely anxiety-provoking for the patient when they're stripped away. In treatment, there was a girl, for instance, who had to eat an apple in 20 bites. No more, no less. This was an intelligent girl. She recognized the absurdity of it, but she also fiercely clung to it on a visceral level. A few other people "had" to cut food into laughably infinitesimal pieces.
For me, there is a positive correlation between the amount of social anxiety or insecurity I'm feeling and the number of muffin pieces that wind up strewn across my plate. Muffins are an easy culprit because you eat them with your hands -- it's like God WANTED you to rip them up into countless pieces, right?
Occasionally it extends elsewhere. Once, on a date, I ordered a Nutella and strawberry crêpe. (When I'd realized that we'd be going to a crêpe place, I spent the rest of the afternoon/evening stressing out because I had just eaten a big meal and wasn't intending on eating anything else and oh my god the world is ending, omg.) I cut it. . . and cut it. . . and cut it. Over and over, until it looked like a crêpe massacre had taken place on my plate. I was aware of how stupid it looked, how childish, but I couldn't help it, and it was embarrassing. And on the outside I could see that it looked like a coy oh-look-at-me-eating-like-a-bird-how-precious-and-feminine scenario, but it wasn't. It was actually more of a you-are-evaluating-me-right-now-and-thinking-I'm-probably-inadequate-and-of-course-fat-so-I-need-an-eating-disorder-way-of-handling-this. This kind of behavior existed long before the advent of my eating disorder, too: I remember being pretty damn young, definitely pre-teenaged, and conflating people-hate-me anxieties with my perceived overeating and high weight. (In reality, I was eating a perfectly normal amount and I was really quite thin. I didn't go on to develop an eating disorder for no reason.)
The crêpe affair actually happened when I was like. . . six months out of treatment. So, suffice it to say, there is still headway to be made in this particular arena. The Ziploc baggie in my pantry full of leftover muffin crumbs from breakfast could tell you as much.