Here are various articles that can be found on the internet on what happiness is and how to enhance it:
web_resources_on happiness.pdf
Questions_On Happiness.pdf
On happiness.pdf
Here's the article Polish students read on the analogy between quantum physics and emotions:
Quantum physics and emotions - an analogy
We had a couple of lesssons related to communication skills which are essential when it comes to living a happy life and getting on well with people. You can have a look and use the scenarios for classes in your schools:
10 ways to have a better conversation
Communication workshop - disagreeing, preparing for bad news, showing sympathy
Questionnaire on communication - instruction
Questionnaire on communication.pdf