What I love about Quark as a character is that he's completely bought in to the culture of greed, and he's morally bankrupt to a point, but the thing is that when it really comes down to it, he will do the ethical thing at the expense of profit. And in Ferengi culture, and in his own mind, that makes him a failure. He's ashamed of it because in the deranged framework his society has instilled in his mind, his natural reluctance to be absolutely cutthroat is a moral failing.
It's a similar thing with Garak, who wants so badly to be a good fascist, to serve the state like the heroes of Cardassian literature he's always arguing with Bashir about. But as much as he believes he wants it, he's exiled because his soul got in the way of blindly taking orders.
And it makes me think of the things I thought I really wanted, the goals I self-sabotaged without understanding why, the failures that haunted me even though I kept good friends and made people happy and generally built a decent life. It's a reminder that failing to get the wrong thing is actually a success.
