Depends how you define greed. Is the boundless greed that wants more, no matter the cost for others good? The kind of greed that leads to the destruction of entire landscapes, slave labor, child work, war, etc. Almost every bad thing can be backtracked to greed.
I would say ambition is what pushes humanity. Greed is a totalitarian form that has no mercy and always an entirely selfish setting.
Yes, the definition is important.
Erich Fromm described greed as "a bottomless pit which exhausts the person in an endless effort to satisfy the need without ever reaching satisfaction."
I would not risk my hard earned income for anything if it wasn't for the possibility that I could one day lead a better life without having to worry about the next paycheck. I take a risk with what I've already made, because of the potential to make a lot more.
Am I greedy? I don't think so. Am I ambitious? Absolutely. Am I a bit lazy? Yeah, I guess. I always look for the easiest way to make money.. but that's not a bad thing. That's smart.
I am not a Libertarian. I am not a holder of bitcoin for ideological reasons. I hold it because I believe that it's a technology with the potential to be truly disruptive, and because of the nature of the supply. That is: I can profit from the success of bitcoin. Why am I not as interested in investing in eMunie, even though I like the idea behind it? Because I don't stand to make as much. I'm an investor/speculator.. just like the "sharks" I say: how does this make me money? If it doesn't, I'm not interested in taking any risk.
That said, I also "invest" in charities and organizations that I want to support for purely ideological reasons. I don't stand to make anything from supporting an animal rights party, but I do help shape the world into what I consider a better place. I can see some people doing the same with bitcoin.. but not me.