Individual Unhappy With New roommate's Karaoke Addiction

An young man in a coffee shop was sharing his displeasure over his new roommate's addiction to karaoke last night. He said that in all other ways the man was a perfect roommate: clean, friendly, and relatively stable. However, when meeting to discuss the open room the individual had never mentioned his love of karaoke or the fact that in order to be competetive in the contests he apparently entered he practiced a great deal. The young man said he had finally asked the roommate if he would mind keeping the music down and the roommate had apologized profusely and promised to use headphones. The man said that this had only worsened the situation as he could still hear the roommate singing though he could no longer hear the music.
One of the man's friends asked if all the practice was getting the roommate anywhere, if, though it was annoying, the guy was any good.
The man said that was the scary part. Not only was he good, he sounded remarkably like the artist he most often imitated.
The friend wondered what was scary about that.
The man said the artist was Dido.