Messages:

I often write here about wanting a penis. Well it appears that I don't need one at all, because apparently I am one!!! It said so in the dew on my car windscreen. Aren't I lucky?

Fuck, I don't even feel any different.

The person who decided to write this with their finger on my vehicle's windscreen was told to get off the property a month ago, otherwise I would get the Police involved. Zedmeister, I recognise your writing, and I find it particularly hilarious that you had to wait until I was away for the weekend to have the guts to trespass and essentially commit an act of vandalism.

And let's get to the other part, the bit that has had me laughing all day:

your a dick

Get back in the classroom, bitch.

Your is the possessive pronoun form. This form is used to express that something belongs to "you". For example, Your graffiti is shithouse.
You're is used as the contraction for you are. For example, You're going to be removed from the property if you ever set foot on it again.

Next time that you want to leave a message for me on my car, Zedmeister, I would advise that you use the correct form you are (or the contraction you're) if you want me to pay attention to your message. I've been a little distracted by the idiocy of it all to take it seriously.

Better luck next time.