Rude, but Hilarious

Last night I was talking to a lady on the phone as I was working. We had a normal, relatively pleasant conversation. As we were about to hang up she said, "muy amable" which means "very kind." It's a common thing to say when somebody has helped you with something and you are saying goodbye. I thanked her for calling and said goodnight. She said goodnight as well, and as we were hanging up she said, "Yo dije muy amable por cortesia, pero no lo eres." (I said 'very kind' to be courteous, but you aren't.) Then, she immediately hung up the phone. I was first SHOCKED because we had had a pleasant conversation and she didn't have any reason to be upset. Then, I was offended. Then I realized there was no reason for me to take it personally, and I started laughing hysterically! I mean, seriously, how random! I had a good time with it. I hope that was her desired effect. Just thought I'd share.