A lot of eminent traders say that there is no holy grail to trading. However, I have one.
When I was starting out on my trading journey, I occasionally had periods thinking I know better than my system rules, and I overrode them. Although one or two of these situations made me money, in overall terms this ended up costing me some drawdowns. These included exiting my positions fearful of losing profits - which would often be at the absolute extreme point of the retracement, or trading larger than what my risk per trade should have been.
My holy grail therefore is not to interfere with my system rules - they were designed for a reason. If I do this, profits will take care of themselves.
I expect this will be a battle for the rest of my trading career, however I know that, the closer I get to reaching that state, the closer I am to reaching my holy grail.