I am incensed by these people.
Why? Because they disrespect the work of other artists, namely the hard-working, seldom-rewarded architects who trained long and hard to do what they do. A large percentage of them barely get to design a bus stop so actually getting a building up (once its gone by the endless building regulations, tenants association suggestions and health and safety redesigns) is a miracle. To see a building in its model form is a wonder to behold and anyone who has sat in an architects office during a design meeting will have experienced the thrill that these new projects exhude. But once up, the nasty pubic fuzz of graffitti render it powerless and obsolete, a reminder of just how culturally barren our society really is.

And, as a culture vulture living here in Prague, it is a double obscenity for me to see the ruin of mediaeval architecture by these vandals.
People come and go, but our colossal achievements in architecture stand the test of time and mirror our society as a whole. In the future, civilisations that uncover our present temples will be saddened at the mockery our youth made of them and the men and women that built them.