Graffiti.

It’s one of Tom Elliott’s pet hates and the 3AW Drive host wants to know why people do it.

So he found out.

It came after a 3AW listener sent in footage of a young man apparently carving his initials into the back of a bus seat.

Mark Halsey, Professor of Criminology at Flinders University, said there were two driving factors behind the issue.

LISTEN: Mark Halsey explains more on 3AW Drive