You've hit the nail on the head. I find the largest amount of time is spent with client interaction : finding out what they want, changing it when they change their minds, revisions again, etc.
Originally posted by michaelwheaton
I could also mimic a design in a couple of hours, but to actually come up with the idea and make a ton of changes for the client adds a lot of time. Writing to content and making many revisions also takes a lot of time. It really depends on your experience and the client.