This is an electrical question. Why do electricians do this?

On many houses (and businesses), the wall outlet has the ground BELOW the hot and neutral. However, on some houses (and some businesses) the outlet is installed upside down. On these, the ground is ABOVE the hot and the neutral. This forces you to plug things in upside down. I know this may seem trivial and both will work, but there has to be a reason, unless there are a whole bunch of dyslexic electricians and the city inspectors also have dyslexia. There has to be a logical reason that some electricians choose to install outlets upside down. What is the reason? Thank you, Jim