To comma or not to comma: that is the question!

A few days ago, Marash Girl received an email from Enila calling attention to           t-shirts that have the following logo on them:

"Let's eat Grandma!" "Let's eat, Grandma!" "Commas save lives!"

Not sure if she emailed because she knows Marash Girl was once an English teacher, or because Marash Girl is her grandma . . . She SAID she sent it because she thought Marash Girl should blog on the sentiments expressed. . . In any case, Marash Girl can only say that she's thankful that because of Enila, she's not referred to as Grandma by anyone, especially anyone who might miss a comma!

And speaking of commas saving lives, Mr. Hayes (English teacher of Newton High School fame who came up with the Newton Plan, a method of teaching [boring] English grammar using slides and the time of only one teacher (the main point) to address large groups of students gathered in the auditorium    -- brilliant, or so they thought!) . . . Mr. Hayes' rule of thumb for when and when not to use commas, Marash Girl remembers to this day:  "When in doubt, leave it out!"  Not quite definitive, and quite dangerous, as you can see from the 
quotation printed on the t-shirt pictured above. All that to say that Marash Girl always over-commas her writing, which is probably the reason Enila sent Marash Girl that email, ending with "Commas save lives!"