we've seen enormous movement by airlines to impose more fees. i think this is pretty extreme. spirit has extreme problems. they pack a lot of people onto their airlines. so overhead bin space is at a premium. they have had more and more people avoid check bag fees by being pack mules on board the airplane. so they are trying to bring some balance back to that. >> taking the joy out of flying for all of us. scott mccartney, a great column. thank you. if you're ever wondered why make people are shy, there's a new study that says you could be born that way. the study suggests their brains work differently. they have a personality trait that leads them to be more in exhibited. it was conducted by two universities in china.