The Grocers' Apostrophe

The grocers' apostrophe, also known as the greengrocers' apostrophe, is defined by WordSpy as "An apostrophe erroneously inserted before the final 's' in the plural form of a word. Also: greengrocer's apostrophe."

Of course it is not just grocers that have a habit of putting apostrophes where they shouldn't be, examples of this erroneous behavior can also be found at restaurants, hardware stores, gas stations and pretty much anywhere there is a sign.

What I find humorous is that no one seems to agree on where the apostrophe should go in the word "grocer(')s(') apostrophe."