I think that graffitis are cool and give some contrast to an urban area, but only if they are well made. For example, you can find a lot of quickly made, just straight-up bad graffitis in underpasses or electrical transformers.
I do not like that kind of graffiti at all. My thoughts on those kinds of graffitis are that making them is vandalism.
But I do like well-made graffiti. It is one of the most underrated forms of art. It is just amazing what people can accomplish with just a few cans of spray paint.