Do you handle rejection well and do you think it's a factor in successful civilian careers?

The thing about rejection is figuring out why if you can.

Sometimes it's not about you, it's about them.

You may be a good candidate, however they may need a candidate who has a different skill set. If they are already strong in the things you are strong at, it can be overkill. They may need an Operations instead of an Admin. They may need a Black Hat to their White Hat. Sometimes it's about price. Rejection isn't always personal. Sometimes it's just needs based. Sometimes it's square peg, round hole.

There's nothing inherently wrong with rejection. Nothing wrong with saying "I'm not right for this organization." Like working with most tools..."Don't force it. You'll hurt yourself, or break the tool."

Handling rejection at work is difficult for me; but, much easier than handling rejection in my personal life.
Being able to have your ideas rejected or strongly questions without affecting your ability to perform is a useful skill in both the military and corporate work environments.
Personally I handle rejection much better than I used to.

A lot rides on the type of boss you have. Some of them only cares about themselves and have a broken moral compass. The rational boss will sleep on it and explain their decision.