Great that you break it down in order for them to clear out what they are talking about. So, according to your explanation, we can clearly see that ambition is much better than greed but too much ambition can occur too for us humans and this doesn't differ anymore from being greedy.
Speaking of greedy, many of us are currently suffering from it even though we know that it's wrong. In life, we should have this so-called contentment so that we won't fail if we are already at the highest peak of our careers. A lot of poor have this trait already but I think they need to try harder because they are still at the lowest point of their lives.
Greed is one of the seven sins, and even if we do not believe in religion, it does bring some sort of consequences that is not nice at all. If you could end up with a lot of money then you could say that consequences were worth it for this much money and cover the difference, but if you are greedy AND not make any money with it, then you will face those same consequences while also not being rich.
I could be a millionaire by this summer, I truly could, but that would mean not only I would be hated by everyone I know, but also probably be sued by many I don't know. Does it worth it? Absolutely not, zero chance I would do it, hence I feel like I am not greedy.