Most from the list, because they are all part of the same thing.
'Greed' to me is an 'emotion', it is also pretty close to 'wanting everything now', 'want instant millions'. Also 'gamble', 'lack of TA' (maybe even lack of FA), not committing oneself, and 'lack of experience' are also pretty intertwined, so your poll doesn't give a great deal of choice.
I definitely woulnd't say it was betting on indexes or gold or forex. People can make money on those.
The biggest downfalls must be poor money management (whether by emotional decisions or lack of knowledge about what constitutes good money management/risk of ruin) and not having (and then sticking to) a positive expectation strategy. Simple as that.