My biggest transgression I won't go into but I can only say that looking back I'm glad that I survived that period in my diving.
My second biggest transgression: I had a three year gap between my intro and full cave certs. After my intro cert I started to get "experience creep". At first I was good and stayed with the gold line and 1/6th's. Then I started diving 1/3'ds, then I started doing jumps, then I started carrying a deco bottle, then moved on to circuits, then I carried a stage in. Finally some buddies sat me down and said, "You're a solid cave diver but we won't dive with you again until you get your full cave cert. There's too much liability for us and you don't want to be the 'idiot intro diver who died while going beyond your certification.' You've got the skills and experience, you just need to take the class and make it formal." This was a wakeup call for me so I set up my full cave class and thoroughly enjoyed it.
What was going though my head? It all happened so slowly that I think I justified it to myself as a natural progression of my abilities:
- "Well, the 1/6ths rule is there so that I don't go too far into the cave. I've been in this cave X many times and have been comfortable - I'll do 1/3's this time and turn early."
- "Well, it's only a 3 foot jump and I'm familiar with this part of the main tunnel, we're going to tie in to a directional marker, and I'm following a more experienced diver."
- "Well, I want to be prepared just in case I get close on deco."
- "Well, it's just a simple circuit with no branches coming off of it, I know how to use cookies properly."
- "Well, I'll just carry this stage for practice."
That path turned into diving 1/3'rds as a norm, much longer jumps into ever smaller tunnels, deco as a normal thing, planning more complex dives, and using the stage to extend my range. When my full cave instructor asked if I'd exceeded my training I came clean and we chatted about it.
Looking back on everything I took it as a big wake up call and don't intend to ever put myself or my buddies in that kind of position again.