need isn't greed. and a good appetite is a healthy need.
the appropriate mindset for investment/trading is to treat it as a controlled adventure: a checked desire for wanting more.
analysis prior to action, combined with the ability to willingly and gladly admit mistake and take loss early, keeps fear and greed out of the trading game. then aggressiveness is called for when price is really going one's way. all that with a workable trading technique makes a winning system.
of all the above, being able to be in harmony and peace with admitting wrong early and accepting small loss or reduced profit, ie, a TOTAL ABSENCE of PRIDE, is what a trader need most. the rest are relatively easier. i have to constantly remind myself of that.
patience and skill takes care of winning while absence of pride takes care of losing.