Beet remembers babby historical!Liszt playing for him. He’ll never say so, but he’s rather proud of Liszt for growing up into a serious artist and composer. You made it, kid.
He’s quite wary of her powers - I’d almost say scared. H!B was deeply hurt many times by confessing his feelings and then being Rejected; in this life, he tries to avoid the topic entirely.
Sort of connected: If she ever used the Rhapsody on him, he’d be furious beyond belief. He hates being overheard improvising (playing out his feelings), he hates being forced to do anything ever; the combination of the two (forcing him to confess feelings) would be devastating. It would be a serious blow to their relationship - she’d have to make it up to him.
Her late night partying and drinking annoys him, partially because she continually interrupts his Coffee Mornings but also because she never invites him. They’d probably be pretty good drinking buddies if she didn’t embarrass him constantly by asking about his love life.