Reasons to be happy

Why I am actually writing something like this on my teaching blog?? I could have used my personal blog to do so.... but.... I am doing it because I gave it as homework to one of my advanced students!!
Why? Just because I get these crazy ideas and people just do it because they never question me!! (just kidding!)
Well, I was talking about procrastination and I just showed him the sketches a girl had made during a lesson.

I just loved the Minion on the picture and I said that there is a great song from the "Despicable me" movie that I found really interesting and I wanted to do something with it with my students,

And then it just hit me!
Why are we happy? You can have a great discussion in class...
Reasons to be happy...
Happy moments (lesson plan over here)

So what does the word "happiness" actually mean?

 hap•pi•ness (ˈhæp i nɪs)

n.

1. the quality or state of being happy.

2. good fortune; pleasure; contentment; joy. 

(from  http://www.thefreedictionary.com/)

Happiness is a mental or emotional state of well-being characterized by positive or pleasant emotions ranging from contentment to intense joy.^[1] A variety of biological, psychological, religious, and philosophical approaches have striven to define happiness and identify its sources. Various research groups, including positive psychology, endeavor to apply the scientific method to answer questions about what "happiness" is, and how it might be attained. It is of such fundamental importance to the human condition that "life, liberty and the pursuit of happiness" were deemed to be unalienable rights by the United States Declaration of Independence.
Philosophers and religious thinkers often define happiness in terms of living a good life, or flourishing, rather than simply as an emotion. Happiness in this sense was used to translate the Greek Eudaimonia, and is still used in virtue 

(from Wikipedia)

My questions on the subject:

• Is the state of happiness permanent  or are there only happy moments?
• Is happiness the same for everybody?
• Or is it one person's happiness is the other person's sadness?
• Do all people want the same things in the end?
• What does personal fulfillment actually mean?
• Does pure happiness (or joy) exist?
•  Is the children's happiness different from what adults experience?