Hmm?

1 goes to bottom picture
2 goes to top
They’re different because of the way the comma is placed, 1 is saying, “let’s eat grandma” that sounds like you’re saying “oh let’s go eat grandma for dinner tonight. 2 is saying “let’s eat, grandma” so basically saying “come on grandma, let’s go eat something”
^so just comma placement
Last question is simply asking how you would feel if you said “let’s go eat grandma for dinner” , should be pretty easily

Hope this helps