1. The positive way of hacking is that you can do whatever you want, the negative way is that it is a crime.
2 A. It is fun hacking other people's pcs, it is more like an sport. 2 B. not having friends, you only rely on your hacking skills. Basically, hacking is like a playgroud for lonely people.
3. Newbie people are usually targeted, since they are new to the WWW world they are easy prey.
4. Buy a firewall.
5. Some hackers just love to play with your pc, others would technically speaking mess your pc to a point that you would have to buy a new one.