Rotating text 180 degrees will put the text upside down.
Why?
...
We don't ask people when they ask about blinking text. Why ask them why they'd
want upside down text?
One awkward alternative would be entering and formatting the text that's wanted,
but not rotated. Then copying the cell and pasting into Paint, rotating by 180
degrees in Paint, copying the result and pasting the image back into Excel.
Obviously only workable for static text.
If the OP receives a suggestion about finding an upside down font, the OP would
need to reverse character order. With an upside down font, the string
So sue me!
would need to be written as
!em eus oS
before changing to the upside down font. Nontrivial.