Worst for me was the very early Windsurfer with pull out centre board, triangular dacron sail and long, narrow boom that was always working itself loose after a while. It was a heavy bugger which I once dropped onto my left foot when removing from the roof racks and I reckon my foot still hurts today when it's cold weather. Weighed the board some time after this and it was 25 kg. It sure hurt.
Not a fast board by any means but at least you all had the same issues when racing/sailing one of these. They improved with successive models and were always a bit of fun when sailing if on the same or similar board. Even took it to Narrabeen Beach and Palm Beach and took it out in the waves, if they were not too big. Realised pretty quickly that you really needed specific boards for that.
Moved to short boards after a few years and enjoyed the likes of Ten Cate Leapers, 8' custom wave boards, Mistrals and nowadays JP, Carbon Art, and Fanatic brands. The advance in design and performance over my 33+ years in the sport has been amazingly good and keeps me interested in doing it.
You don't always have great days out there but it should always be fun, if not you're in the wrong sport.