I am greedy. That is why I gamble for only small amounts. If you want money gambling is about the dumbest thing you can do because if you don't stop the house will eventually win.
That's what I thought when I read the OP. If you're completely greedy and completely rational, you don't play -EV games. You do whatever maximises your expectation, and for most gambling games that means not playing them. Obviously there are a few exceptions, like countable blackjack, games with large progressive pots, games involving skill (poker, etc.) but for the vast majority of gambling games the smartest strategy for the greedy player is to walk away from them.
But when someone trully has the edge, BR management becomes crucial. I've known quite a bit of "good" poker players and bettors who went broke just because they only had the knowledge and expirience, without having the mental toughness and discipline to absorb the inevitable losses.
Its a pretty tough area to get better at. Exprience helps, but in the end, some people just cant deal with the net loss and can not avoid chasing.
Or in other words "variance is a bitch".
When Just-Dice first launched, I knew we had a 1% house edge, and was careful never to let the house risk more than 1% of its bankroll on any single bet, but still the bankroll took a hammering. After over a billion bets the site's profit was less than half of the expected 1%, and it was hard at tims to have the "toughness and discipling" to be confident in the long term outcome.
I can't imagine how much worse it would feel to be playing poker. Then you have so much more scope for self doubt to creep in. With the dice site I knew the odds were in the house's favour. Playing poker when you hit a losing streak it must be easy to start thinking "maybe I'm not as good as I thought I was; maybe I was just lucky before when I was winning" and such like.
and its fun... 
Break even mentality is a form of greed anyways. 
