We are all actors. Shakespeare said it so it must be true. Some of us are method actors- so deeply embedded in the characters we've assumed that we don't think of it as acting. And some of us wake up in the morning and put on our daily faces in full or at least partial consciousness that we're playing a part. Could we wake up and choose to be someone else? Theoretically, yes. And practically too. Confidence tricksters do it consciously, people with multiple personalities flit from persona to persona without conscious control.
For the sake of the game it's important most of us stick to the roles we've chosen and developed. A few wild cards add spice to the mix but the game would become unplayable if- like Alec Guinness in Kind Hearts and Coronets- we were all of us flitting between roles- a playboy one day, a suffragette the next and a pedantic clergyman after that...
Last night's dream blew the whistle on me. You've chosen your role, it said, and you'll play it through- but, look, you could have played this other character if you'd wanted to.
Maybe next time.