Barbershop quartet was having a revival during the 1940s; I'm not sure an asthmatic before inhalers would have been in such a group, and there wasn't a lot of 1940s for Steve to be indulging in hobbies what with missing the second half. Steve however is a walking case study in snark, which is one take away from Civil War worth having. (cf the Queens-Brooklyn exchange on the tarmac)

It's sort of like Natasha baiting Steve about "who's the girl?" regarding Peggy Carter's picture next to Howard's.