Ask the Little Bald Bastard

Dear Little Bald Bastard,
  Long time listener first time caller...
  What is the proper way to bludgeon a co-worker without getting in trouble or looking like an asshole?
- the quiet one
Dear quiet one,
  Physical violence, while often satisfying for the soul, is a hobby that you can't really engage in without being punished. You're better off employing the threat of violence to change a co-worker's behavior. If your description of the threatened injury is sufficiently explicit, you can generally bend people to your will without the effort (or evidence) of inflicting actual harm. This tactic also allows you more flexibility, since you can threaten poisoning or other methods that aren't predicated on actually being able to overpower your workplace nemesis.
  This is how a lot of the torture that our intelligence agencies absolutely do not engage in would work if they ever dabbled in it. You convince the victim that she will be injured in messy, painful or rude ways if she doesn't cooperate. If you're persuasive enough, your captive begins to squeal like a newborn piglet.
  The advantage you have over our hypothetical agent is that you're not looking for information. You won't have to corroborate testimony that may have been fabricated to avoid torture. Once you convince the offending cubicle-jockey to stop tapping her pencil, or humming aloud, or eating celery at her desk, your work is done.
  Don't forget to cover your tracks. Include the caveat that you'll pass out pain like a supermarket free sample if your co-worker tells anybody about your coercion. Fear is a fantastic motivator, but fear of losing your job should motivate you to be discreet when threatening to maim a co-worker.