I wear a baseball cap almost all the time. Usually with John Deere or Baltimore Ravens logo on it. Or maybe a farm store, or hunting supply. I follow most of these basic hat rules. Take it off when meeting someone formally, when eating at any table inside, during the national anthem, prayers, or pledge of allegiance. I also take it off whenever I enter a building (except for barns, farm/hunting stores, or very big stores) and decide, once inside, if it's appropriate to put it back on or not. Usually when it's just me and a bunch of friends I will leave it on when walking into the house or anything like that, because we are all fairly young and none of us really find disrespect when we all know it's okay to eachother. When I get to a customers house, I always take it off my first time in, but if going back and forth to the truck with tools and the like, it will most likely stay on even when inside. I do know there are exceptions to most of these rules, and I don't find disrespect in any of them if someone else keeps it on, but I know some people do and that's why I take mine off. The one time I will never excuse leaving a hat on, is when the national anthem, prayer, or pledge is being said. I will ask you to remove it.
Another thing, I wear jeans to anything. I know I can look nice with a collared shirt and jeans. I also took a liking to Carhartt Dungarees and some camo pants.
One more thing, the hat backwards. I wear it backwards sometimes, depending on the hat and the rest of what I'm wearing, including what I'm doing. I don't see anything wrong with that, as long as it's an okay time for it. I wear it backwards all the time when doing farm work or hanging out with friends, but I would not wear it that way to a job interview, for example, unless I took it off during the meeting.
Kyle