So many people's idea of decorating a corner is to just put a plant there.
Almost every room has a corner and they are great little spaces to create intimate, interesting spaces in a room. You can do so many creative things if you just look at the space and envision what could happen in that corner. A reading chair and a lamp are always great option, as well as a stand with art. If the corner is large enough you can even build in small corner seating arrangement.
I'm not sure I believe in Feng Shui, but the ancient Chinese claim corners are the storage energy space of your home. They say the far right corners are the love space and the far left corner is the wealth space. So if you are single and broke you may want to look at your corners carefully!
Just don't leave your corners blank and forget about them. Corners need your attention too.