I don't want the amount of friends you have determine how successful you are in your career, but I do want strong friendships to bring benefits into your sims life.
These benefits should be based on the friend's, traits, skills, career, and wealth.
You can get occasional phone calls that will give you boosts for work, moodlets for skills, and they can give you occasional gifts to show their appreciation. If you interact with them in a group activity, you get a boost for whatever that activity normally provides.
This way you will probably be more choosy about your sim's friends.
Sims with negative attributes should have negative effects on your sim, like bad advice that goes predictably wrong.