I like to think the freedom to form your character comes from the fact that your past is gone. The Back When Times are over, and everything you thought you knew is gone. You awake in the vault with a new life, all alone, with no idea what's been going on for 200 years.
-Some will choose to focus on finding their family
-Some will choose to decide they are dead and forge their own new trail
-Some will do a combination of both
-Others will do something different.
-It's been confirmed we can have romances with companions, so we can literally commit infidelity, which will create some interesting situations later on if and when we find our family again.
It's a perfect fish out of water situation. You may be a soldier with some experience in warfare, but all the experience in the world can't prepare you for the war did to the world you knew. Or thought you knew.