Re: Barry and Caitlin
"Yeah, uh, you know I love you, Caitlin, but singing in public really isn't my thing."
Not unless he had to. Sure, he'd watched tons of musicals as a little kid and knew that he wasn't bad at it, but he wasn't the kind of guy who really liked the spotlight. Even as the Flash he hid his identity and didn't brag a lot. He really wasn't the most confident guy in the world, despite being a superhero.