I had a vendor slip a delivery date once and ended up being very angry with him on the phone. He called back a couple hours later and started the conversation

I had a vendor slip a delivery date once and ended up being very angry with him on the phone. He called back a couple hours later and started the conversation with, "I am concerned." All my anger evaporated. Later I realized I was mad because I felt he was minimizing my requirements and needs. Simple but powerful.