Well, then the sweeter version is to mosy out as they are leaving and introduce yourself and proceed to sweetly talk their ear off. For most people it would only take twice for them to never park in front of your place again.
Unless you make a new friend, which is also good.
I can't see the parking lot from my apartment, though my front door is 50 feet from my car. If I look out my security door (too cold for that, now) I see a 6' high picket fence around my patio.
My solution has been to park behind the offender, leaving enough room for them to get out. It works, most of the time. Except for the one dingbat preacher who was very un-Christ-like about it all. He doesn't park in this lot any more, but he is parking wherever he wants in the other lot, and making a whole batch of new enemies.