We all know how Jack ventured into the clouds and encountered the giant. He became filthy rich and enjoyed his life after killing the giant. But in actuality, the giant was a strange being who hated humans. This led to Jack wanting to convince him of humans' goodness. The giant, however, did not believe him. This drove the giant to give Jack his treasures in return for leaving hm alone. Jack did, but told stories about the giant.
Several others, determined to see if the stories were true, ventured up the beanstalk. There, they found the giant and stole his new treasures, causing him to chase them, which led to the giant's death.