Corner upper cabinets are sometimes a waste because they are hard to reach. A window goes so much better. It is possible to "chop" a corner, leave the foundation and roof square, put an under-mount sink in a 45 deg corner, and have a nice window in front of the sink. The plumbing can even be re-routed through the back side of the cabinets if the original sink was close by.
Outside the house, that extra bit of foundation is a great base to mount a bird bath.
Here is a vid to describe better:
45 Deg counter top install with cast iron/porcelain under-mount sink
Also, a view from the outside where a sculpture or birdbath could be mounted: