"About the only other thing I'd want would be a wider neck. My fingers are so fat that sometimes I deaden the string next to the one I'm fretting"

This quote by Terry Kath is describing the instrument he plays, more than likely a guitar. He is sharing his wish for a larger neck on the guitar, as his fingers are as well big to conveniently fret the strings. He is saying that as a result of his huge fingers, he occasionally inadvertently numbs the string alongside the one he is fretting. This can be an issue for guitar players, as it can cause the notes to sound stifled or muted. Terry Kath is sharing his desire for a larger neck on the guitar, as it would make it easier for him to play and also would certainly help him stay clear of unintentionally numbing the strings. This quote shows the value of having the right instrument for the job, as it can make a massive difference in the high quality of the audio.