The power of a bus pass

I really like (and rely on) public transportation so I thought this joke was pretty funny. I wish everyone a very happy Saturday! 

One day, Dave, the bus driver, was in his bus when the biggest man he had ever seen got on. The giant looked at the driver and growled, 'Big Eric doesn't pay' , and took his seat.
Dave was only a little man and he didn't really want to argue.
This happened for several days. After a week, Dave was beginning to get a little angry. Everybody else paid, so why not the big man?
So Dave went to the gym and started a course of body-building. He didn't want to be frightened of Big Eric any longer.
Eight weeks later the driver had strong muscles and was feeling very fit.
At the usual stop, Big Eric got on. 'Big Eric doesn't pay' , he barked; but this time Dave was prepared for him. He stood up, shaking slightly, and said between clenched teeth, 'Oh, yeah? And why doesn't Big Eric pay?'
'Because Big Eric has got a bus pass', the man replied.