I like graffiti - even random tags over blank walls because it’s a sign people are truly living and breathing in a space.
As long as there have been walls there has been graffiti. Spaces without graffiti are artificial and antiseptic.
I like that part of it too - but feel that if I owned a building and had people spraying paint all over its exterior whenever they felt like it...maybe not so much.
Graffiti on things like trees (e.g. in urban parks) is awful and trees are the opposite of artificial and antiseptic. The main problem with graffiti is that most of it is made without thought or consideration, and that never ends well.