Animals can be very docile and very ferocious. Just like humans, it just depends on what their mood is like on a particular day.
Recently, a man learnt that it doesn't matter what you're doing, danger is everywhere. He was walking on the street, with an attache case in his hand, probably going to work, when a wild boar came out of nowhere and attacked him.
The boar just appeared in front of the man and pushed him down on the road. Then he attacked him repeatedly and just ran off.