Breast augmentation is one of the more common cosmetic surgeries in the military. I actually knew someone who had hers reduced in size because they were too big and interfering with her life. Plus, wearing heavy flak vests with armor plating is painful if you have boobs, and next-to-impossible if they're massive.

I also had another coworker who got implants because she said her flat chest was affecting her mental health, self-image, and confidence. Now she's one of the more confident and outgoing people I know in the military.

The most common surgery, actually, was LASIK/PRK eye surgery. For most of my career, it was considered a cosmetic surgery. The military defined "cosmetic surgery" as any unnecessary surgery a member elected to have done. You didn't need to fix your eyesight, because the military would issue you glasses. So it was cosmetic.

However, in the last handful of years I was in, someone successfully argued that getting your eyes corrected would improve your effectiveness at work, and thus was a benefit to the military, not just the member. Plus, they started allowing people to become pilots if they had the PRK surgery. (You need perfect vision to be a pilot, and eye surgery used to ban you from the job.) So eye surgery is no longer a cosmetic surgery.