The creator of 'Grey's Anatomy' and 'Scandal' describes the moment she came into her own as a boss

Shonda Rhimes once almost made a terrible career decision.

Today, Rhimes pretty much owns Thursday-night television, with her hit series "Grey's Anatomy," "Scandal," and "How to Get Away With Murder." Her latest show, "The Catch," premieres Thursday, March 24.

In her 2015 book, "Year of Yes," Rhimes takes readers back to the days when she was casting "Grey's Anatomy" and still somewhat unused to the experience of being the boss.

Rhimes explains that everyone on the team was pushing to cast a particular actor as Cristina Yang, one of the doctors and main characters on the show. This was before they'd even met Sandra Oh, who would eventually go on to land the part.

Everyone, Rhimes said, thought this actor was great - and a perfect fit for the role.

Here's Rhimes:

I, too, thought she was great. But I did not want to cast her. Now I know what I did not know then - at this level, everyone is a great actor; there are no bad actors, there are just actors who do not fit your vision. This actor was just … not the key that fit the lock that turned the story in my brain.

Rhimes kept telling people she needed time to think, largely because she feared voicing an opinion that was different from everyone else's. Needless to say, the rest of the team was getting frustrated.

Rhimes' casting director, Linda, suspected what was going on, and called her to say, "This is your show and if you cast someone you do not want, it will not be your show. You need to tell everyone no."

When the team gathered on the phone, Rhimes hesitated before finally blurting it out: "No."

Though they were surprised and still tried to convince her otherwise, no one got especially angry or turned against her. Instead, her producer expressed relief that Rhimes' enthusiasm had returned and that she'd finally made a decision.

The next day, the team met Sandra Oh.

"That was my very first no at work," Rhimes writes. "Because of that NO? I decided that I was steering the ship. And I started behaving that way."