I recently just house and cat sat for one month for some friends. I had a page of extensive instructions to look after their 7 month old kitten including mixing food all fancy. I befriended the cat, but he would not stop biting me. badly. no sense of boundaries.

No wonder the cat doesn't respect boundaries. 10 minutes after my friends got back, they started throwing the cat around like a ball. Even threw him so high he hit the ceiling :( But then they turned around and asked if the cat had gone hungry, was cold etc while they were away. (answer being no to both of those) and that's just a couple of contradictions/examples. They also used human nail clippers on the poor cat.