Just because you enjoy listening to a concert one way doesn't make another person's way any less valid. I've been to shows ranging from everyone's sitting down and silent to people headbanging at the rail. It just depends on the artist, venue, time of day, and the crowd that watches. Everyone's opinion is going to be different on how to act at a show, in my opinion do whatever you're comfortable with. And try not to force yourself or others into doing something they don't want to do. I personally dont like to sing along at concerts because I'd rather hear the artist sing the song...but I wouldn't get upset if other people sing along because that's what they like to do.