I attended an introduction to scuba at a hotel pool in Hawai'i and did the introductory exercises. I had no trouble with the introductory skills, but the others did, so I swam around and had fun after each skill while he worked with the others. I eagerly signed up for the Discover Scuba dive the next day.
Well, the next day was Easter Sunday, and no one else signed up, so the instructor brought along his girlfriend. We violated the Discover Scuba depth rules as I did a full on 75-foot dive. It was fantastic, and I said that, yep, I would sign up for certification the next day.
That afternoon my wife and I found a beautiful deserted beach and discovered a key rule in Hawai'i--if a beach is deserted, there's a reason. I am sure there are now signs warning of the dangers of a shore break, but I had no idea then. I fought the surf, and the surf won. That evening the scuba instructor saw me in a sling, and my goal of certification was over. (My AC joint tear was permanent.)
That was many decades ago. It was 14 more years before I got certified.