Your Hair
Civilians are free to choose the kind of haircut they want, but soldiers don’t have the same freedom. They are required to get the same buzz-cut hair in active service. Once they get out of service, they can actually choose to get a new haircut, but most of them will probably stick to what they’re used to.
Scanning Situations
Soldiers are trained to scan and assess any situation first before they act. They first find what sticks out from the ordinary, then if needed, they act. So, when your soldier does this when you’re out having a picnic in a park or in a concert, don’t be surprised. That’s just how they are wired. No biggie.