>>639
Real answer: the em dash (―). It makes writing so much more clear than having commas all over the place. Unfortunately, it's rarely used outside of print, and as far as I'm aware it isn't taught in schools. I suppose it's because of how difficult it is to type, and even the ASCII approximation (--) is dying out.
Dokyun answer: the interrobang (‽).

>>641
What is your favourite Unicode character?