Why monsters extract tolls for crossing bridges

We're on the edge of greatness — xain-russell

"Dragon: “HALT TRAVELER! THIS BRIDGE IS UNDER MY CONTROL! PAY THE TOLL OR CROSS THIS RIVER ELSEWHERE!”

Knight: “Nay foul beast! These are the lands of men! I shall pay no such toll, and what’s more I shall slay you rid this land of your tyranny!”

Dragon: “TYRANNY!? FOOLISH MAN! THIS BRIDGE IS OVER A HUNDRED YEARS OLD AND IN DIRE NEED OF REPAIRS! THE STONES ARE ERODING AND THERE ARE TERMITES IN THE WOOD!”

Knight: “… what?”

Dragon: “I GIVE THIS BRIDGE ANOTHER FIVE YEARS BEFORE IT COLLAPSES! I’D RATHER AVOID THAT AND PREVENT SOME POOR HUMAN FROM GETTING HURT!

Knight: ”…“

Dragon: “THE TOLL IS TEN GOLD PIECES.”

Knight: “… Okay.”

Dragon: “ALSO, DOWN THE ROAD, A FRIEND OF MINE IS RAISING FUNDS TO FIX A FARMER’S ROOF! IF YOU COULD ASSIST THEM AS WELL WE’D BE VERY GRATEFUL!”"