If people are going to park on the street, they need to park in front of their OWN house

Neighbour constantly parks in front of our home when they have just as much street parking as we do. Also, we both have driveways. Except we have a walkway down our front lawn and he parks his car right at the edge of it.

Why do people do this? Park in front of your own house if you want to be on the street.