The other day I walked into a restaurant, wanting breakfast, and looking for a table. The sign said please wait to be seated. It didn't appear busy. I heard from down the back, "sit anywhere you want." Thinking nothing of it, I proceeded to sit down.
There was a sign hanging over the cash register that said, "To our valued customer, we will do what it takes to make your experience with us as pleasant as it can be".
I noticed the waitress and the cook standing together talking. When the waitress appeared about ten minutes later, with her hands filled with dirty dishes - she asked, "What do ya want?" To which I replied, "a coffee and a menu. She responded, "I'll get the coffee and why don't I grab the menu from the table beside me. I felt like I was intruding on the two of them.
Poor customer service aside, your words, voice and actions need to match or be congruent. If they don't, you'll send mixed messages. This happens when someone says it's not what you said, it's how you said it.
In communication the only thing that matters is what the other person believes and feels about what you said. If they receive mixed messages, the best thing you can do is apologize and start again.
My point is, ask yourself are your words, tone and actions helping the person understand you or are they hurting you? Deliver it well and it will be well received. You want the message you're sending to be the same as the one the other person is receiving, don't you?