Photoshop is the alpha and omega of photo editing apps, but every once in awhile someone comes up with a way to do a specific function even better than Adobe.
A case in point is PhotoScissors, a US$19.99 Mac app that makes it easy to remove an object from a photo, then paste it in somewhere else. This can be done in Photoshop, and I marvel watching pros do this. It takes more than a few steps, and can involve the Photoshop Magic Wand or the Quick Selection Tool.
PhotoScissors works differently. Take your photo, and paint some broad green strokes on what you want to preserve. A remove tool is used to paint red on objects you want to remove. You often want to remove a background, while you want to preserve a foreground object or person. The app does a quick smart analysis of what is highlighted, and quickly gets rid of the unwanted background.
There are lots of reasons to have a tool like this: product photos, separating objects from a background, creating an isolated image with a new background, etc...
I tried the app on a variety of photos, and it worked well. It's not always perfect, but with a little effort you can clean up anything that is missing in the cutout. PhotoScissors is often faster than any other method I've used, including Photoshop.