What is it ? I dont pretend to know, but one thing is for sure, it means different things to different people.
In this 21st century world we live in i think we have lost the meaning of the word. If i get the latest gadget, that will make me happy, but for how long? Not long i fear.
Getting back to basics would be a great place to start, for instance think about the important things in life. health, without good health i dont think you would be that “happy”, but one persons perception of good health is completely different to someone elses. For example if you had life threatening cancer that would be a really bad scenario right, but if you were in remission a virus that knocked you over for a couple of weeks wouldnt even rate a mention on the sadness scale compared to what you have previously been through.
So we all have a different perception of what happiness is.
We should be getting back to basics, love yourself, your family, be the healthiest you can be by eating well and exercising and start to realise that nothing or no one else can control how happy you feel but you.
At the end of the day being happy or unhappy is just another one of the millions of thoughts we have every second of every day.
You can either go through life with the glass half full mentality or the opposite, its totally up to you.