Always let your baked goods cool to room temperature before wrapping them or closing them in an airtight container. If you don’t the cookies (or brownies, muffins, whatever) will get super soggy. They’ll also stick to one another so instead of having a few dozen cookies, you’ll have one giant cookie blob.
It won’t taste as good (because, soggy), and it will bring “Ugly Desserts” to new heights that you probably aren’t looking to explore.
Ugly Desserts 