Power
As an international aid worker, you're often going to find yourself in positions where you're powerless. After all, you're up against things that are way bigger than you are: poverty, corruption, ignorance, disease, violence, war, and death. Because what you're fighting against is so big and sometimes intangible, you may find yourself feeling overwhelmed and cynical about the career you've chosen.
So, you have to learn to appreciate the small things. Anytime you help to heal a sick child, or get food and water to a starving family, or teach a woman to read, you're exerting some power—even if it's just a little bit—over those global problems that are so enormous.