It's possibly unintentional, but I've always liked the fact that Joker has multiple faces in Persona 5.
1) During daily life he's reserved, calm and quiet. He has his fair share snarky comments/moments of action, but his body language generally screams passivity.
2) As a Phantom Thief he's flamboyant, confidant, smug, and a total daredevil. Obvious.
3) Inside the Velvet Room he drops the confidence he displays as a Phantom Thief,
but he isn't passive either. I like to think that this is his true nature, given his lack of glasses OR mask.
Intentional or not, it's neat how it ties into the "people have 3 faces" concept fairly well.