Nobody else can change you, but you can change yourself. There is a lot of good stuff from Positive Psychology about learned optimism and how cultivating happiness and positivity is something that people do have to work at, and how to do that.

:: Authentic Happiness :: Using the new Positive Psychology
Martin Seligman's website

http://enjoylifebook.com/
An easy to read book by Lynn Johnson, who also has a newsletter you can subscribe to about cultivating a more hopeful attitude (info for subscribing on his website). I have been to one of Dr. Johnson's workshops, talked to him personally, and I use some of his materials with my clients. He is a real person who has even written back to me when I responded to his newsletter emails.