Being a dick to the person who calls isn't going to accomplish much. They hate their job already, and have no responsibility for the script.
dingojoe is right that signal-jamming is the most effective thing. If you want to mess with the people creating the push poll, indicate that the least persuasive stuff changes your opinion, and the most persuasive stuff doesn't. Give them answers that indicate their messages are ineffective, like claiming you changed your mind away from the candidate whose push poll it is (although you usually won't know that upfront). That kind of thing.
That's basically what I did, though telling them I was strongly against the NRA and strongly pro-choice probably didn't screw up their numbers too much.