Postcards are a simple, yet decorative way to mock people who are not on vacation with you. With just a single piece of paper and a small amount of postage, you can take a tropical paradise and shove it in someone else’s face. Some people think that you send postcards to brighten a friend’s day. But a friend’s day is not brightened by a reminder that he is not in Hawaii. A friend’s day would be brightened if you sent a postcard showing you being violated by airport security.