When your kids were little, back-to-school shopping was (in hindsight, at least) a breeze. You checked everything off the list of required supplies. You tossed their favorite character backpack in your cart, maybe even a matching lunchbox. Bing bang boom, you were done. Everyone was delighted. Then the tween years hit. And teenage-hood. Now they have so.many.opinions. The level of specificity they bring to conversations about everything from water bottles to earrings is enough to make even a seasoned negotiator sweat. But, ya know, you’re still Mom, and you still want to buy some things for yo...