I personally am enthralled with the difference in my art from when I work from one of my photographs, and when I work from what is in my head and what wants to evolve on the page. I can faithfully reproduce photographs in a painterly style, they look realistic with proper color and crisp edges and definition and what not. But when I just go for it? Completely, completely different style of expression.
It has taken me awhile to decide that what I do without a reference is still good. No, not fishing for compliments; just sayin'. I think most artists struggle with whether or not their work is good enough. Depending on who your teachers were (if you had any), different emphasis is placed on different things. I had a teacher who was bent on realism being the best thing. She could do abstract, and she did encourage it.... but realism was the way she wanted us to go. You had to learn the rules and be able to draw before you could break the rules. So, I got really good at realism.
Fortunately I also had a professor later who looked at my thumbnail sketches, and then at my final product one day and he scratched his head and said, in front of the whole class, "I don't know- I like your thumbnails better." and he said more, but right there- he liked my thumbnails better. The things I drew from my head without reference. He could point out in the process the minute I started using reference photos. It lost the character and the unique style and became something anyone with a photo could do. I don't think I can ever say how happy I am I decided to take that last class at KVCC. I had already graduated, I didn't need it. I just -wanted- to take it.
... and that's enough introspection for the day!
