"Town's Favorite Gas Station" joke

Legend has it that football great Bronco Nagurski opened a gas station upon retirement from the NFL.
A visitor to town asked whether or not he was successful.
"Once someone gets gas from Bronco, they never go anyplace else", a local told him.
"Is the service that good?" asked the visitor.
"No, not really." said the local.
"Does he have the best price?"
"About the same as everybody else."
"Then the gas must be better."
"No, it's just regular gas."
"Then why does everyone keep coming back to Bronco?"
"Because when Bronco Nagurski puts your gas cap on, no one but Bronco Nagurski can get it back off."