Years ago, I worked with a teacher who was excellent at what she did. She loved the kids, she had well developed lesson plans and used her resources brilliantly. I learned a lot from her.
But, there was one thing she was unaware of. Her volume. She had gotten into the habit of raising her voice at the children quite often and quite harshly at times. Being unaccustomed to it, I remember being startled and bracing myself the first few days I spent in her classroom. She used yelling as a tool for control. In my concern for it, I remember lifting up a small prayer about it.
A couple days later, she sat down with me and said, "I want to apologize. I had no idea what I sounded like!"
She went on to tell me that she happened to hear herself through a tape recording at home. She knew that's what she also sounded like in the classroom. Being able to listen to herself objectively made her suddenly aware of what others had been hearing all along. She was embarrassed and humbled. From that day on, she was more conscientious of her volume and her classroom took on a much more relaxed feel.
Lesson learned: How beneficial it can be to listen to yourself (even if it's not through a recording). You might be surprised by what you hear.