“So I sit quietly, agreed politely”

Katy Perry – Roar Lyrics on LyricsMode
EXPLANATION
Pretty self explanatory, but she's again saying that she's not telling anyone what she's thinking, she would just do what ever she was told to do and never say no. She is being quiet and going with the flow and agreeing with anything.
EXPLANATION
She just agreed with everything that the person said. She never said anything else to contradict their idea.