Following the show’s 30th anniversary, Julianna Margulies has her New Yorker attitude to thank for her breakout role on E.R. The Golden Globe winner recently explained why she “was pissed” during her audition for the Michael Crichton -created NBC medical drama, which ran for 15 seasons from 1994 to 2009, and how that helped her land the role of nurse Carol Hathaway.

“What happened was, I was in LA. visiting a boyfriend,” she recalled on The Kelly Clarkson Show . “I had three auditions that day, and being that I grew up with a hippie, crazy, wonderful mother, who was always late.

.. I’m usually early, because I never want to keep anyone waiting.

” But Margulies quickly grew impatient, noting there were “probably 50 people in the waiting room, and they were running two hours behind.” Just as she was leaving, the casting director called her name. “I rolled my eyes like, ‘Oh really.

’ So I went in to audition for a recurring character, but I was so pissed off that I did it really rudely, a little New York anger,” said Margulies. “I knew I’d flunked, and I walked out of the audition, and the casting director said, ‘Hold on a minute, you’re not right for that part,’ and I was like, ‘Ya think?’ But they said, ‘You might be right for this head nurse, Carol Hathaway, but she dies in the pilot. Could you come and read for that?’ So I went back in and I read for Hathaway with a lot of attitude.

And I got the role!” And although Carol died of .