Most people have been in a situation where too many drinks required a taxi ride home. Instead of speaking incoherently and not remembering where you put your money as you arrive alive, put the 'Dear Cab Driver Napkins' to use.
Not everyone has a sober person to put them in a cab when they're incapable of doing so themselves. The 'Dear Cab Driver Napkins' allows people to fill in their address so that the driver knows where to go and where to get the money when the rider is too drunk to do so. Of course, the problem is that this requires the honor system to be in effect considering the location of your cash has been clearly marked. However, if you're a trustworthy type of person this item will be of some use--just don't put money in your thong or underwear.