Quote from nutmeg:
I believe you can conquer fear with knowledge and understanding. If one fears lightning and thunder, understanding lightning and thunder will alleviate the fear.
If you fear a particular market/trade, you can wait it out on the sidelines or as understanding becomes greater you can remain in the market longer under adverse circumstances when other "sane" {:>) people are out.
Greed on the other hand, perhaps it is more emotional origin than fear, or has greater external and internal ego influences.