As a chemistry graduate I have long believed that emotions both good and bad are just chemical reactions, and although not easy to control, they can be controlled.
Habit is also something that I find interesting, and the video below (at 11min 5 secs ish) looks at getting in the habit of being positive and all the benefits that come with this, including being better at learning.
The 21 days program ( 2 minutes a day) suggested in the video includes:
1. Every day write down 3 new things you are gratfeful for.
2. Journalling about a postive experience you have had overthe last 24 hours
5. One act of kindness – write a positive email or tweet thanking them.