Curiously, what other reason is there?
Well there is always finding something you think you will be interested in.
HS student walks up to recruiter and says "I want to work with computers"
The recruiter responds "Well I have the perfect thing for you.... (recruiter pulls out brochures) Nuclear Power"
HS student "That doesn't sound like working with computers"
Recruiter "But look instant advancement to E4 and STAR re-enlistment worth E5 and up to $45,000(1999)"
I don't blame the recruiter, I was the fool that traded my interests for dollars. But in doing so I learned a valuable lesson, if you hate your job it doesn't matter how much you get paid.