What does an IT manager do

I have been a Network Administrator for the past 8 years and currently hold a Senior Network Admin position with a great company. There are currently 3 individuals in our IT department including our manager and junior admin, my question to all of you is what is the responsibility of an IT manager other than playing games all day and taking credit for all of the hard work that his admins do. This is not the only time that I have come across an individual like this in such a position, who knowseverything about nothing.