If you're on page three of your search engine for what to write in a thank you card, we've got you covered right here. For wedding thank you cards, Christmas thank you cards and new baby thank you cards, we'd recommend something super sweet for family and friends. After all, they've shared your special days with you and they can keep your personalised thank you cards on their mantelpiece to look back on. For funny thank you cards, try an inside joke only you and the recipient would understand. No knock-knocks.