people would gather dozens of cats in a net and hoist them high into the air from a special bundle onto a bonfire. According to Norman Davies, the assembled people "shrieked with laughter as the animals, howling with pain, were singed, roasted, and finally carbonized."
It seems all classes of society (even the king) took part in this form of entertainment and it was considered perfectly normal to attend such an event. These people weren't abnormal perverts who enjoyed cruelty to animals. They were good citizens by the standards of their time.
A few centuries later we find the thought of burning cats outrageous. I wonder which of our current pastimes will people a few centuries from now find outrageous. And hilarious? Considering the example above I wouldn't dare to guess.