Why?

I was walking on a busy street 2 nights ago, running an errand for my mother, I ran into some problems and had to talk to my mum on the phone in order to clarify issues. My handkerchief was in my second hand, the direction of the traffic was facing me. A public bus was coming towards me and as usual, the conductor was hanging on the entrance. As I was talking on the phone, the conductor was staring at me from far, he was holding a jerry can with his free hand. I was wondering why so I thought maybe he wanted to snatch the phone that I held to my ear so I held it tightly and tried to shift as the was about 2 speed past me. All of a sudden, as the passed by me, the conductor smacked me hard on the hips with the jerry can. I was so dumbfounded, the smack was very hard and painful. I just looked at the conductor whose bus had already gotten ahead of me, he was still staring at me. Another pedestrian that saw the whole incident just told me to forget about it and move on.
As my hips kept hurting, I couldn’t help but think. I did not know the guy from Adam, never seen him before in my life, why would he derive joy in inflicting pain on me for no just cause. Why are some people just wicked? It doesn’t make sense, am still in shock. Please, do u have an explanation for me?