It was supposed to be the greatest day of Carl’s life – finally, his parents said he was old enough to go on the big dipper ride at the fun park. But! Carl’s parents let his little sister go on the ride the same day! Is it fair that she only had to wait to be 8-years-old, but Carl had to wait to be 10?  How do we tell the difference between something being truly unfair, and something just... making us feel jealous?