If you are doing something with a gun that incites fear, then yes, the cops can and will come talk to you. And depending on what you were doing, they can charge you with a crime. There’s a very vague law about “brandishing” a firearm in most states that they can use to charge people who are being assholes.

Most of the time you see an open carry, which is far less common than concealed carry (for obvious reasons), nobody even pays it any attention because it’s somebody who needs the attention to feel masculine.