Not a grumble but an interesting illustration of the importance of commas (see the classic: Let’s eat, grandma). When I first read the first sentence below, I assumed Elmo was the object of tickle, and so assumed that the comma was a mistake. But of course it’s not. But it does change the meaning. The comma makes the Elmo a direct address, i.e. Elmo is being spoken to rather than, if there were no comma, the audience being to spoken to about Elmo.