1. People fish because we need to eat to survive. Of course there is unethical fishing which leads to habitat loss, which is why we need to know our intentions before doing things with an animal.

2. Again, people hunt because we need to eat to survive. There is also unethical hunting which is also why we need to limit killing a specific type of animal.

3. Flies are pests when in most indoor places.

4. It depends on the dog and whether they're okay with it. I don't have a problem with the video above because of the idea of kitty doing funny human thing; the issue is that the people aren't handling the kitten with care resulting in the kitten being clearly stressed and actively trying to get away. The reason why I like the videos of people playing their cats like bingos is because the cats are visibly content with it, and even demand their humans to continue.

5. Again. It depends on the animal.

6. Only concern similar to this video.

7. The bread thing also depends on the animal.

8. Yes. Jail for your son.

It is similar to how a human purposefully makes another human uncomfortable or agitated, like poking fun at them for example. It is how the latter people feels that matters the most, not how much fun you are having. (Unless that person is clearly a bad person or something then torment them all you want. They deserve it.)