I've always loved graffiti.
For a long time I have kept an eye out for graffiti tags. I don't tag anywhere myself, but I find the messages people choose to display publicly fascinating. Whenever I take my camera out, I go graffiti hunting!
(Disclaimer: I don't know what they mean, that's part of what makes them interesting! I do not condone hate speech, racism, sexism, homophobia, etc. and if I post a symbol or phrase that does, please let me know. That's the opposite of what I believe in.)