I think this is very good example, I got this friend who we are
in the same level of work. One day my manager just said to him:"you
take over me for 1-2 hours I going for meeting"
Then my friend act as if he is the manager, telling
everyone to do work. The thing is he wasn't joking, he is really
talking and instructing us, telling us to do his work for him. From
then on nobody really liked him.