The scariest flying moment - or rather the most stressful - was bringing a PA12 sea plane back into the dock with an FAA examiner onboard, with a brisk wind trying to blow us off the dock and some kids deciding to be messing around in a boat right where I wanted to be....I had to decide where to cut the engine and drift, and I had just buggered my neck getting in the thing so did the whole flight test in pain! Luckily the FAA examiner jumped out of the back seat and onto the jetty to stop us drifting off and it all worked fine and I didn't chop up any kids (and I passed the test).
Other than that, the seaplane rating is the most fun flying I have ever done!