"...why the words "Go Go" are pasted on the wall."
The words aren't pasted on the wall. The are attached to that thing that looks like it's coming out of the top of that bald guy's head. If you look closely, there are two other plaques going perpendicular to the "go" ones. Looks like a revolving sign. Maybe the other two say "stop"...part of some office party game...or the solution to some office traffic flow problems.
Art has a double face, of expression and illusion.