All those lousy customers that came before me
Laura points us to the FAQ at FourPawsDesign (click the FAQ button near the top left corner).
Unfortunately, we can no longer take phone orders. Customers forget to tell us something and after the order is placed and processed they claim we wrote down incorrect information. By placing an order online we have a record of exactly what you want, especially for custom-designed items, leaving no room for error.
Part of being in business is being harrassed and annoyed and even burned by the customers that you had yesterday. Of course, if you hold that against the customers you hope to have tomorrow, it's going to be awfully hard to grow.