InterestingThe good thingsThe cause and the passion is definitely there. You will learn the reality of humanitarian work, its perks, and its limitations. You will also learn the incredible drive and the human limits when it comes to helping people.
The challengesWages and career progression, relatively, is below your average corporate job. You will also be disappointed with the bureaucracies that you faced and the sentiments some would have about your job. Lastly, you might be discouraged by the lack of appreciation by others.