How many times have you been engrossed in your hobby and someone has asked you this question? It's common if you are using a tripod and almost guaranteed if you are using an arm length lens. While it is flattering my stock answer is "I'm a happy amateur with a hobby that has gone wild." Giving it more thought I would say I prefer being a happy amateur without the stress of everything that goes with being a professional. Think about the difference between working for a living and being on vacation. When are you having the most fun?