this was actually many moons before I had developed rigoruous trading discipline. I have a note taped to my screen: "Never a bad day if you follow your rules." One of the rules I adopted over time was to quit trading a certain system for the day after 2 consec losses, and to limit any 1 day's loss to 3%.
The door in question resulted after a day where I lost twice on a certain system, while simultaneously breaking my rules for stop loss%. Furious, I traded twice more, and lost twice more. Finally I gave it one more shot and lost again. The net loss was 0-5 and exactly -$2000 for the day. At the time, this was a 10% loss in one day. That was the last time I broke my rules, and I haven't had a bad day since. I made it all back the next month. That's two months of sweat and tears to break even.
I've kept the door as a reminder : )