

This might sound nuts but, programmable/shifting tattoos.
Like, it could detect elevated levels of cortisol in your blood or increased heart rate and then just gently pulse or warm up to a comforting temperature as a way calm you down or remind you to breathe. Or light up like a custom RGB keyboard, or change colors/holographic effects depending on time of day. Anything really.
Per the Wikipedia article:
TL:DR for the rest of the history and rationale: Most of this was rich people wanting more time for their personal hobbies, other people’s sleep and health be damned.