Some rules for interface design: Don’t allow users to make obvious errors, don’t provide them the means to make errors, limit their choices to only the ones that are relevant (or even correct), provide them flexibility within the confines of their task or goal, don’t introduce unnecessary complexity or redundancy (in terms of information or elements – the arrows I’m using in the video have no reason to exist), adhere to accepted conventions, and that’s just to name a few. How, then, did this travesty of a birthdate entry form come into existence? Who bothered to spawn it, and why? How bad could it possibly be? See for yourself, and marvel at what it provides.