A place I used to work had a barber opposite it, that had a big sign that said
OPEN MONDAY'S
and it always annoyed me. One day I pointed it out to the proprietress, and she insisted that OPEN MONDAY'S was fine. When I pointed out where she was wrong, she went apeshit, saying that I obviously didn't know what the duck I was on about, and to shut my face.
So, I had a copy of Eats, Shoots & Leaves sent to her shop, and unfortunately I screwed up on postage and she ended up getting stung for Ā£1.79. She moaned and cried about this for a week, so eventually I posted her Ā£1.79 in pennies.
But OPEN MONDAY'S continued to haunt me.
Eventually, after some font research, I replaced her OPEN MONDAY'S sign with a practically identical OPEN MONDAYS. After two weeks she noticed, and again, went apeshit. Insisted on the replacement of her original sign. So I gave her a nice O'PEN M'ONDAY'S' sign, which she did not appreciate. The police were summoned. I have a lifetime ban from her establishment.