Amateur vs. Professional

I was thinking about the boundaries between a professional and an amateur, and I decided that what I thought was the difference was this:

An amateur can take something great, if given the chance, and make something not-so-great, while a professional can take something not-so-great and create something great.

I was thinking about this sense in photography, as you don’t need the best cameras to take the best pictures. This also applies to other things, which I’m sure you can think of.

What do you think defines the line between professional and amateurs?

Edit: Nice to see people chiming in with their ideas. For the rest of you don’t be shy, you can still comment.

I will be posting so more material soon, I just need to find some. You are welcome to email or IM me with ideas.