zombie drifting

When you go shopping for no reason and 'drift' around, but zombie drifting is when your hungover or half asleep and the only thing you can concentrate on is putting one foot infront of the other. one thing that can break a 'drift' is when someone says hello, where you can wither not reply (if your that zombiefyed) or reply with "halro" or some slurred version of hello and keep walking. The person that said hello usally think you dont like them.