OT: Hey You Weirdos!

[AgentZero]

Greetings fellow deviants and miscreants!
I require a little assistance in the creation of wonderfully depressing story that came into my head the other day. The basic story arch is: Man is in love with woman who is barely aware of his existance. Through stealthy manipulation, man destroys everything that matters to the woman, her relationships, her job, her reputation, etc, while slowly working his way into her life so that in the end, he is all she has left. But then of course he discovers that by destroying everything that she loves, he's also destroyed what made her the person he loved.
Now, what I need from you, my friends, is as many truly awful things you can come up with that would profoundly mess up someone's life. Obviously it needs to all be stuff that can be done from the background. Walking up to the boyfriend and shooting him would effectively remove him from the picture, but would hardly endear our character to the woman he loves.
Only a few specific things that I'd like to ask.
Names of any drugs known to drastically increase human aggression and violence.
Things one could be convicted of that would not not carry a terribly hefty sentence (ideally something one could resonably expect to get a suspended sentence for), but that would likely cause the loss of one's job, and create great difficulty in getting a new job.
Any 'minor' infractions that happen to carry a whopping fine if convicted.
Any offences that would result in the revokation of a driving license, but again a minor (if that) prison sentence.
Those are the specifics I'm looking for, and of course any other nasty things you can come up with to screw up someone's life would be greatly appreciated.

Disclaimer: The above request is strictly for research purposes in the creation of a work of fiction. Any responses to said request will not be used by the author towards any real person, and said responses should not be used by ANYONE to cause a real person any harm whatsoever.