I hum to myself nearly constantly. If it’s not the song stuck in my head, I’ll just make up a tune. I quite like it, really.

The latter, I believe.

Exactly

Me too. Usually changing the script slightly to exaggerate or be bombastic works for me. Ex. “How are you today?” “I’m doing just fantastic so far, how are you?” Or “ch-ch-ch-chillin,” sung to the tune of the Chia Pet jingle. Usually gets me further than “Good, you?” Social interaction is just another game I’ve had to get good at.