I'm reading this:
http://www.spring.org.uk/2008/05/how-to-choose-happiness-combat-5.php It's about how everyone can be happy if only we make the right decisions. Then they give reasons why people bad less than right decisions: biases.
Research has uncovered four common belief biases:
The contrast effect is the often incorrect belief that a good experience will be more enjoyable when it follows a bad experience (and that a bad experience will be worse when it follows good). Research on jelly bean tasting showed this can be a mirage.