In that episode, after Cuddy risks her job by allowing House to give the patient steroids and the patient surviving, House calls her in the middle of the night to tell her the diagnosis and she ends the conversation with a 'Goodnight, House".
The odd thing is that, House actually replies ("Goodnight, Cuddy."). It is seen all through the seasons that he only says that to Wilson, and well, I got all exited and stuff when I realized he said goodnight to her.
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