English is one of the few things I'm really any good at, and all those mis-spelled signs, often with superflous apostrophes, seem to draw my eye like a magnet.
I have quite a collection of 'Aberrant Apostrophe' pictures now, and present them here for your interest and elucidation.
I've taken the vast majority of these personally, and only a very few have been contributed by others.
Here's what apostrophe usage is all about:
ISN'T is 'is not' - and not isnt or aint. It's IT'S - if you mean 'it is'.
It's ITS - If that's not what you mean. It's HERS - it isn't her's.
It's OURS - and not our's. It's YOURS - it isn't your's.
It's THEIRS - and not their's.
So there...