One letter changes so much

As subject-verb agreement goes, this is a pretty major offense:

In all fairness, I'm almost 100% certain that the final A just fell off this sign.  Even the centering is off without the extra letter.  The sign is in such good condition otherwise, though, that it does make you wonder.  Maybe it was scraped off by a grammar-hating troglodyte.

Because only a troglodyte could hate grammar enough to do something like that.