"The fact that you were able to ask the question "How much is too much?" Shows you haven't lost touch with your background or basic values. "
How much is enough was the question I asked of myself and my biz partners. But your point is appreciated, I try to keep in mind where I began, how I got here. The "arc of life" as the World According to Garp noted.
All of us at reach an utter low point at some time in our lives, when we feel we don't have a leg left on which to stand. I may be naiive, but have always believed that if you live your life true to your understanding of right and wrong, when you do reach that point, you discover that you DO have that leg left, after all. It's something most of us don't even think about, but that sturdy leg is there all the same.
Maybe it's from all that psychological training, but it seems to me that's the problem of people like Martha, Hillary!, Hanoi John et al.: when they're 90 years old they'll be looking back over a sea of regrets. They'll find no comfort in knowing they at least did the right thing.