That’s a great meme and I too was sitting there pondering the comma. I think it adds a little pause that makes the timing work better. But it’s definitely against the rules.
;)
There are great memes but some of the spelling errors (for example) just make them unusable, a lot of the time.
Sum of them caws me to grone. ;)
Typos? Hey, I’m grate(!) with those! LOL