Coworker Relationships
One thing no one tells you early in your career is how insanely valuable your coworker relationships become after you leave a company.
They know your strengths & can call your bullshit. And once you're no longer coworkers, work-related complications/considerations disappear.
Friends you haven't worked with are great for encouragement, but when it comes to your career, no one knows you like former coworkers (duh).
Source: https://twitter.com/ashleymayer/status/859914112741982208