My friend actually got up and walked out this morning over this question. Even after showing him the chart and demonstrating the only possible outcomes, which he accepted, he still couldn't reconcile it in his head, and so refused to believe it. He wanted to take the 'agree to disagree' route, but of course there is no arguing with math. This is a person who is passionately for evidence when it comes to creationism, ESP, and the like, yet when presented with something that countered his intuition, he wanted to let his intuition trump real world data. He is always asking me how people can be positive about God with all the doubt there is, and now he has experienced that himself. It's very hard to overcome what seems right in our heads.
Later, what finally convinced him was raising the original choice to one in a billion. With those odds, it's very unlikely the person picks the car first. He was able to agree on that. After we go through the process of eliminating all other boxes but one, I told him he couldn't switch. He had to stay with his original odds. This way, he was able to retain his doubt that the first pick overcame 1/billion odds, and recognized that to take advantage of the 50/50 he needs to switch.
I then asked him the 'daughters' question, and he got it wrong and wanted to argue, even after showing him the outcomes. So even though he learned to overcome his intuition in one case, he didn't learn the value of questioning it. If it is this hard to get a person with a skeptical disposition to accept something as certain as math, imagine the challenge we face in getting people to question their intuition on matters like god, health, or consciousness.