Explain to me or Zen is not just for believers anymore!

Just give me 5 minutes of your time. The other day I was sick - just did not feel well. I stayed home from work. About mid day I decided I needed some comfort food. I took a small trip to the store of grocery - perhaps gone for 15, 20 minutes. When I came back to the house, a condo I suppose is the appropriate word - I just never thought...oh well that is not the point of this rant...when I came back, there was a car in our MARKED ONE parking spot. Now this has happeneded before. We live a few doors down from a very nice guy that teaches music lesssons to kids. Often the parents will pull into our spot to drop off a kid, pick one up. I have on a few occassions heard him tell parents to not park there as it is his neighbor's spot - I appreciate his efforts and thoughtfulness. I just wish that the parents would have the same thought process. Now, let me explain...there are several, a plethera, no wait A CRAP load of unmarked available parking spots in our parking lot for those that do not live there, pay rent or a mortgage, visitors to park. Yes it is true that the unmarked ones are not directly in front or the closest to the actual dwellings, but they are not far either. So here is my wonder, my question, my inquiry, my perplexing emotion, my irate command, a insistance, my petition, a prayer, my request, a solicitation even, my urge, and opinion welcome...don't you sort of want to hit me upside the head with my new thesaurus?
What makes a person think, the idea to form in the head of, that it is ok to park in a marked space, that obviously matches the condos? I was mad at first, they were there for 35 minutes...I even thought I am going to write a note. then I sat on my couch and stewed for a bit, calmed down, looked at my dog...no note, I am sick and the last thing I want is some agitated mom knocking on my door and making fun of my handwriting! The anger truly did turn into wonder and then amazement. I mean really, I would never go visit a friend in a neigborhood of houses, and think, "well my friend probably does not want me to park behind them and even though their house is where I am going, ah hell I will park next door in their neighbor's driveway" I let it go. I did, well sort of as this entry can atest to. If it happens again though I am not sure I will let it go so gracefully...