Being idle

"Idle mind is devil's workshop" is really true in my case.
Being idle in job is the work is the worst possible nightmare for anyone in his first job. After sometime one gets into the rut of doing nothing and its very difficult to come out of it. I dont get the idea why these IT companies keeps on hiring people to put them in bench. In my view a person who has got into a new job will be raring to go, once the neccessary training is imparted. But by keeping him/her in a bench for a long time will sap out the enthusiasm and by the time he gets a project he needs to get out of the rut into which he has been pushed into.