I once read a story about the future!
Brain cybernetics were common. If you were "average" you got average brain implants. If you were wealthy you got the latest-and-greatest tech. It was illegal to replace implants (or add new tech) at a later age. One of the characters did so anyway (ended up being hired as a hacker for one of the major leaders in the book). He had a phrase like, "doc, you might as well just close my skull with a zipper 'cause I'll be back" or some such.
Kids coming out of hypersleep/cryogenics would turn on their implants, which turned everyone walking around them into NPC characters in their games, and start running around playing games.
The book had a strong theme about sanity, mental disorders, and how they were embraced productively rather than shunned socially. I remember an old guy who painstakingly re-drew his tattoos rather than having them permanently inked because it would drive him nuts seeing them go blurry with time (he also overfocused on his work and had to be told to eat, he drank something frothy).
The protagonist was a multiple-personality. One of them was, well... randy. (Sorry, I'm a guy, we remember stuff like that.) Getting the multiple personalities to work one-with-another to get the protagonist out of trouble was a key theme in the story. One of the personalities was stark raving mad (considered socially to be a bad thing), but ended up being useful because the madness allowed her to see the dangers lurking in "hyperspace" (I'm not sure that was the word used) so navigators could avoid them. The madness of one of her personalities was critical in saving the ship near the end of the story.
At a guess, I read this back in the mid to late 90s.