I would put knowledge in the first place. Every trading problem can be solved with knowledge (including emotions). No matter how good or experienced you had become, you will always need to read more.
Since there are 3 ways to lose all of your money, I would arrange them as follows:
- Not taking care of a losing position (no closing manually, no stop-loss, without a hedge, no reversal signal)
- Irrational position sizing (including leverage)
The last problem is
- Being a Forex trader only
There are good opportunities in the currencies no doubt about that.
But there are other markets where your chances to make money are bigger.
- The worst problem is the one you don’t know even exists! So it is better to learn those 77 problems and see which one is currently hurting your trading.