Funerals send messages. They're your last message to your friends and family. Planning your own funeral is a huge comfort to them since they know it is the last message you want them to have. If you care about them, you want them to recieve the right message. It provides closure. It's not pretentious. It's not about you at all, it's about those you love, and it's entirely selfless. See how comfortable you are with your own death when someone you love dies.