Per Snopes.com’s entry on the “16 Things…” list (found here) and Barry’s website FAQs (found here), these items originated in a piece called “25 Things I Have Learned in 50 Years” and can be found in the book Dave Barry Turns 50 (1998). The “16 Things…” list is a popular email which has been edited and rearranged so much in the 15+ years since its creation that Barry’s website states he “…wrote something like it…[but] you can no longer count on anything in it being Dave’s actual work.”

The original piece (including all 25 items) can be found here.