We need more relationship kinds that aren't family or dating.

So many options are still possible here, why should it all be about friends, family and dating? 

The only one we have that's none of those is enemy. 

I'd like to see a few new ones added, to better define other relationships instead of needing to have them merely implied. I have a few suggestions there: 

-Rival. 

Depending on how well they like the other, it could be a friendly rivalry but also a bitter rivalry. It would make enemies more interesting when there's also a rivalry going on. Rivalry can also be one sided, and could be fully dependent on traits so it won't just pop up where it makes no sense. Like active sims could see another sim performing better than them in sports as a rival, the average sim would not care if another is better than them at sports. This could add a lot more depth to traits. 

Genius sims could compete to see who is smartest, self absorbed sims would not want other self absorbed sims to steal their spotlight, etc. Jealous sims could develop rivalries of all kinds though, and the paranoid trait could just amplify feelings of rivalry from their other traits. 

It would come with unique wants, wanting to prove they are better than their rival in some ways. Like getting a specific skill up higher than their rival, getting a better paying job if materialistic, a higher ranking job if ambitious, wanting to beat them in a game, etc. 

-Boss/Employee. 

They really need to open up more household styles, I think many of us have had an employee sim of sorts part of a household? Like a live in butler, maid, bodyguard, apprentice, etc? Would be nice to be able to define that relationship in CAS, or have sims be able to hire another. What for could be left pretty open, could just be listed as employee. Would be up to the boss to define what kind of working relationship they have. Could be casual, professional, strict and maybe other options too. 

Best to keep plenty of freedom in what the job is though, by keeping it as a basic employee description, so we can make of that what we want. The boss can offer praise or scold them for their work, can fire them too which means the employee leaves the household, the employee can also quit.  It could be impossible for relatives to be employees, but it could be possible to be romantically involved with an employee. Once engaged or married, they'd no longer be an employee though. 

It could come with new interactions too, the boss could always tell the employee to do stuff, but the employee can't do that the other way around. If the relationship is set as professional or strict, casual interactions won't happen between them. They would never automatically talk as friends, the employee might even stand at attention when the boss enters the room. 

-Rolemodel. 

Especially for children it could happen often, and they might look for it. To them, this sim is just the best and they want to be like them, taking any advice from them to heart even if it's horrible advice, they are also extra hurt when their rolemodel is mean to them or worse: Disappointed.