Answer: I was offended once when a friend used something I told her against me.
Explanation: I remember talking to a friend once about a difficult situation she was going through and giving her advice. She used something I told her once against me at the time to make me understand that I shouldn't advise her in that situation. After she told me that, my perception of her changed since a person who uses the things you say to attack you is someone you should be careful with.
