I feel this way about voices where you can hear the 'wetness' in the voice, for a lack of a better word. Hearing a person swallow, open their mouth, very voice-y voices, that are obviously coming from a very organic being.

mrcreepypasta, who I enjoy - I can only listen to a few of his videos at a time, and depending on how he sounds in that video, sometimes I have to shut it off completely.