You can't blame the guy. Anger problem is common, depending on
the situation that provokes us to react with aggression. In this
case, EZlink is a personal item considered by many. So judging from
his reaction, he's protective of his own items because they are
something private. So letting an outsider tactlessly or brainlessly
snatch away his own belonging of course can result in the arousal
of aggression! Simple cause and effect psychology no one even
knows.. now I'm telling you all lor. 
On the other hand, the bus driver has lousy attitude. I once
encountered such bus drivers. I think too many already and I've
lost count of them. When I was a teenager, I use thread to break
the driver's legs when I see him one more time. But now, I've toned
down. All I did was ignore them. One would even come all the way to
the back seat where I was sitting and talk to me. I was like wtf???
Can you please carry on your job well and drive? I continued
ignoring him, and in the end he bo bian have to drive the bus and
not waste other people's time.
Can't imagine paying so much and yet getting some bus drivers who
are incompetent and yet so "garang".
Oh by the way, I've to add: Sometimes, we forgot exactly how much
we have in our EZlink card so by giving it a try on the buses,
(beep-beep) no go!!. Nvm, we then check our wallets. No coins or
lose change. So what now? Chase us out of the bus while the rest
are waiting in the queue?
So lau kui (lose face).
There ought to be a solution to test EZlink's left over amount at
the bus stop so that people can pay up efficiently rather than
having fights like this.