Talking to more and more people it looks like happiness is the same and totally different for each one of us. Both in the same time. We all have different memories which connect us with happy and fulfilling moments and in the same time we all relate happiness to people, sharing and contribution.
I invite you to see what Tom answered me about his happiness. Tom dedicated a part of his life to help others and this is part of his happiness. It was a pleasure for me to talk with him. Enjoy!