I chose military service instead of a mission. At that age, I was more comfortable with the idea of being a Marine, and possibly a Marine aviator, than being a guy in a suit and hat knocking on the doors of strangers who would rather that I didn't.
Having done splits with the missionaries, I found the work stressful and tedious, to say the least. And I'll admit that the idea of making money instead of spending your savings for two years was attractive as well.
As the LDS Church has drifted right, slipping into irrelevance and even disrepute in the wider world, I'm more grateful each year for the choice I made. That said, it has been a long time (if ever) that a Marine has made me as proud to be in that fraternity as the Staff Sergeant pictured below.