If you want to make buttermilk ice cream, you will have a dozen leftover egg whites. So then you'll decide to make angel food cake, which is oversold as a fat-free dessert. Of course you will start thinking that cake would be delicious with buttermilk ice cream.
Also, you might not own a tube pan (nor really want a tube pan) and decide it might be fine to try a silicone bundt pan instead. Inadvisable. We may be having angel food french toast for breakfast tomorrow.