u/makosidan

So I have an interview and a friend of mine he works for morrisons said that if I get the job then I should walk around with the EXACT same attitude and facial expressions as the guy in this gif. I asked why and he said managers insist on that attitude and that his manager asked him to walk around behaving exactly like he is in the gif. I said why again and he said its obvious and wouldn't expand any further. Why would it be considered good for a staff member to walk around the shopfloor like this? What vibe would that give?