In Thailand it can be hot and sweaty. A light weight thin piece of fabric can absorb that sweat around your head of wrist. On a motorbike you can use it as a scarf to protect your mouth from flies and dirt. In busses it can be chilling cold because of the airconditioning. Then you can use it as a scarf to give you some extra warmth. When sleeping in a bus or hostel you can use it as a blind coffer for your eyes. Also suitable for naughty sex games.
http://thailandoutdoorshop.com/catalog/product/view/id/7015/s/buff-thailand-outdoor-club-limited/