I can answer for these. Hideo enjoys himself by hanging out with his gang; starting fights and wreaking havoc are just what the gang does collectively. Hideo himself has other hobbies, as seen in his skills. It's not that he doesn't like anyone that's not in his gang, it's that people outside of his gang are typically put off by his abrasive demeanor. Really depends on the individual.

As far as the "rape ghost" thing goes, I myself am not terribly satisfied with it, but I couldn't come up with a significantly better solution. Though an easy solution to your issue is that shinigami as individuals are as different as any other people would be, and only Hideo's father in particular is a distrubing rape ghost.