Good question. I think that for many people there is no single reason. In my case, I had done two two year active duty tours from the Army Reserves in Superheroes The Dachshund League shirt to earn money to continue my college studies (missed Korean War GI Bill by 23 days). Completed by BS Electrical Engineering while taking R.O.T.C. Decided I could do at least as good a job as an officer as many of the officers I had served with and could serve my country as well. Disappointed my parents at first since they thought I should go into civilian work as an engineer. They later decided that I had made a good choice, particularly after they spoke with my last boss who gave me a glowing report.