The act of creating is not the difficult part in the photography business.
Sitting in your office waiting for the calls/e-mails to come in, that is the difficult part. I know, there shouldn't really be sitting in this situation. It should be all about running around trying to sell yourself to every Tom, Dick, and Jane on the street.
But after you do that running around, isn't there a moment where you sit and wonder "Will this ever take off?"