The Wikipedia page for "Shut Up and Dance" explains its background. Singer Nicholas Petricca based the song off of an experience at a party in Los Angeles. "We were at the bar, and it was taking forever to get a drink. I was frustrated because there was great music playing and I wanted to be out there." Apparently his girlfriend suddenly pulled him out to dance, inspiring the chorus and title of the song. Later, Petricca remembered his high school days of being a "dork" to complete and round out the song. Petricca said that the theme of "Shut Up and Dance" is "Encouraging people to let go of whatever it is that’s bothering you and get into your body and out of your head." I think that this song is about being free and in the moment, and appreciating the people around you. It shows that when the speaker just "shut up and danced," he realized how important his "discotheque Juliet teenage dream" was to him. If she hadn't physically grabbed him and made him dance with her, focusing only on her, he wouldn't have had this realization and it would have just been another boring day. A link to the full description of the song: https://en.wikipedia.org/wiki/Shut_Up_and_Dance_(Walk_the_Moon_song)