1.  Deadlines, 30%.

2.  Their job's life-or-death implications for another person, 17%.  Obviously this doesn't apply to a lot of us, but it matters to people like police officers, firefighters, and soldiers.

3.  Competitiveness, 10%.

4.  Physical demands, 8%.

5.  Working in the public eye, 8%.

6.  Growth potential, 7%.

7.  Risk of dying on the job, 7%. 

8.  Hazards we encounter, 5%.

9.  Meeting the public, 4%.

10.  Travel, 3%.