Anyone interested in reading more on this topic should check out Adam Grant's Give and Take.

Incidentally, one of the interesting takeaways from the book is that if you look at plot of people mapped to career success, you'll find that benevolent givers dominate -both- ends of the distribution. The theory goes that those who are in the left tail got there by being too preoccupied with others' needs, to the exclusion of their own success. Conversely those in the right tail got to where they are both by helping others and by consistently asking others to help them. In the latter scenario these folks have harnessed benevolence as a strategy for career growth, and the collective goodwill "out there in the ether" nets out to measurable success over the long-run.