I’ve spent nearly three decades cultivating food habits that would make Miss Manners yartz up her crumpet. I dip my fries in enough ketchup to blanket the shores of Guam. I spit cherry seeds into my trash can with a ping. Just yesterday, I took a large bite out of a block of cheddar cheese, leaving the rest of the block in the fridge with a noticeable half-moon bite mark. But no behavior is quite as shameful as the Burrito Suck, my preferred method of bean extraction. At least, I thought it was shameful—until I realized I’m not alone in...