The ability to enhance or modify photos is something of interest to us all. Family photos to big business can benefit from the digital age.
For family photos removing/adding objects or people, enhancing colours or adding a soft focus can be the difference between an image that is just one amongst many or the family portrait enlarged and hung in pride of place. 
For business, when trying to convey an idea, often words are not enough and drawings not quite sufficiently accurate. We are a visual creature and the best way to communicate an idea is to give your clients a photo realistic image that looks exactly the way it will be.
I gain a great deal of pleasure creating mock-up images for business. These images are often the difference between gaining approval on a project and not.