Once upon a time many years ago my wife took voice lessons for a semester or two in the school of music of the local university.

There's no denying that she learned many valuable things. Unfortunately, the lessons also caused a significant change in the way she sang the traditional ballads she had learned from her grandmothers. She applied what she had learned and started singing them like art songs. I didn't like what I heard. She lost what I can only describe as an "edge" and the ballads started to sound pretty instead of powerful and moving and haunting. To my ears it took her several years to get over the lessons and get back to the sound that I thought was appropriate for her traditional material.