I recently encountered both some truly wonderful and some truly awful singing. Neither of the people singing (a man, a woman) were my students. I have no idea how they came to be in the circumstances they were in. The wonderful singing in the man, who was probably in his early 40s, and the awful singing in the woman, who was probably just barely in her 20s, were in two different classifications (music theater/jazz and classical) and two very different locations, thousands of miles apart.
It is particularly disturbing to hear a young person sing so terribly when she clearly has no idea that things are as bad as they are and no way to fix them. It is particularly satisfying to hear someone sing so well that the voice is totally at the disposal of the man as an artist, expressing text and music with great skill and expressiveness.
If reactions from others count, I would say that those around me agreed, as the one performance was greeted with a standing ovation and the other with polite subdued applause.
After nearly 40 years of teaching singing, I should think that nothing would bother me, but it is never the case. I am still deeply in love with singing and with singers and all singing, whenever I hear it, goes directly into my body via my ears and my heart. I am often so moved, (plus and minus), that it takes me days to get over a specific performance, shaking it loose from my mind. This is, perhaps, a virtue and a curse — a blessing and an obstacle. I am inspired and I am chagrined.