My first thought is, "Go ahead and help them raise money for their troops. You were a Girl Scout. You know what it's like to have to sell those very last boxes. Wouldn't it be nice to take some home to your family? It's for a good cause!
My wiser second thought is, "Those cookies are a lot better in their hands than on your hips. You know that once you open up that box; it'll be nearly gone in one sitting and they won't even make it home!"
Thankfully, I've been going with the latter thought! I quickly say a prayer, "Oh Lord, please help me to not buy any of those cookies!" Then I speed walk in the opposite direction before those Samoas (a.k.a. Caramel deLites) start calling my name! :-)