[High Praise! to Mental Floss]
18 Things to Look For the Next Time You Watch Jaws
Note: some indelicate pictures at the link. Jaws was only rated PG, but that was before PG-13 was invented. It’d probably pull an R-rating if it were released today.
[Think you have a link that’s IMAO-worthy? Send it to harvolson@gmail.com. If I use your link, you will receive High Praise! (assuming you remember to put your name in the email)]

I think they got #18 wrong; that is, they’re laughing because they’re relieved to still be alive and to see each other alive.