In uniform or out? The vast majority of people walk around without a gun and aren't scared in normal clothing, there's nothing to be scared about unless you're in the woods hiking.
Active shooters, terrorist attacks, or other officers in need of help always run through my mind. The day this happens, the last thing I want to say is "I wish I had my gun." I could never live with myself if I chose not to carry that day, and knew that people died because I decided to not carry the life saving tool of my profession.