Can I use my powers for good? I hesitate to ask this question, but I read a lot of the career advice from MathOverflow and math.stackexchange, and I couldn't find anything similar. 
Four years after the PhD, I am pretty sure that I am going to leave academia soon. I do enjoy teaching and research, but the alpha-maleness, massive egos and pressure to publish are really unappealing to me, and I have never felt that I had the mathematical power to prove interesting results. However, I am really having trouble thinking of anything else to do. Most people seem to think that the main careers open to mathematicians are in banking and finance. I really want to work in some field where I can use mathematics, but it is also important to me to feel like I am contributing something positive or at least not actively doing harm. For this reason, financial speculation is very unappealing to me, although I do find the underlying mathematics quite fascinating.
Here is my question: what careers which make a positive contribution to society
might be open to academic mathematicians who want to change careers?

You may want to consider moving to a country where there is a lack of trained mathematicians. I'm sure that many of these countries have the problem of their best minds being drawn away by exciting overseas opportunties. The universities in these countries are probably less focused on research and more focused on the pragmatic task of upskilling their workers.
