So Much Louder In My Head?

Here is the scene. I am in class, hour two of the 4:30 to 8:30pm marathon session. My stomach is cramping... I am so hungry. I scan the room: a few people on laptops, a few with water bottles out, but unfortunately none eating. Damn. Do I really want to be that guy? I look down to see the 3/4 filled ziploc bag of Giant Cheez-its peeking out of my backpack. I came prepared. I open the bag and that salty-cheesy baked smell tickles my nose. What's the big deal? I think to myself. It's just a little snack, besides, the instructor did say it was okay to eat during class. I leave the open ziploc inside my backpack so as not to draw attention. I grab my first handful and discretely put it to my mouth. Crunch... uh oh. The first bite sounds like a boot hitting gravel. Is anyone looking? I continue chewing, but as I do so the lone boot turns into a platoon of soldiers making their way down a gravel road. Crunch...crunch. Crunch, crunch, crunch. Now I'm paranoid, desperately trying to figure how loud my chewing is but all I see are blank faces. Even if I did see a disapproving look it doesn't matter now. After that first tasty mouthful I have lost all self-control. Another handful, crunch...crunch. But I can't enjoy it. I am so focused on the volume of my own chewing I can no longer hear the instructor. And if my chewing is drowning out the instructor, why isn't everyone staring at me? And why isn't their a label on the Giant Cheez-it box warning of the GIANT crunch? I try chewing slower, but it's no better. Gravel wasn't made for sneak attacks. A few painful minutes pass. My eyes dart around the room like a drug addict as I finish my Cheez-its. Aware of my own ridiculousness, I still can't stop it... Even when I know it was probably so much louder in my head.