My nightmare companions on a desert island would be people who would never cease yapping about nothing, are overly tactile and Are argumentative for the sake of it.
Choosing between equally friendly people, one only talking when necessary, or the other talking non-stop, give me the quiet one. My brain would melt otherwise. Mental peace is good. Yapping is torture.
Likewise, overly tactile people, eurgh. 'Nuf said.
People arguing for the sake of it... Just. Go. Away.
A combination of these three... Nightmare for me.