How pretentious, It's their money, they can have what the fuck they like. if your going to get precious over your design become an artist, you can advise a client but it's just that 'advice'. Selling your concept is a vital skill to have, just because a client does not share your vision doesn't make them morons, they may know a lot more about their target market than you do.
My advice is to work with a client, ensure that you both share the same vision and idea for the design and work on communicating how your work meets the requirements of the brief