“Happiness” is high on the list of what everybody wants. Many people maintain they will be happy "when" - they get the new house, but they won't. Then they will be happy when they get it completely furnished - but they won't. They'll be happy when they have added the playroom, but they won't. Next, they'll be happy when the mortgage is paid off - but they won't. There are many people who will be happy "when" - they are able to take that vacation in Hawaii - but they won't, because it doesn't make any difference where you go, there you are.
Happiness is neither a "when" nor a "where." It must be a "here" and a "now." George Burns said if we were to ask enough people what would make them happier we'd get answers like a new car, a bigger house, a raise in pay, winning the lottery, getting a face lift, having more kids, less kids, no kids, etc. He points out that probably not one in a hundred would say it would make them happy if they had a chance to help people, and yet he says that might bring them the greatest happiness of all.
The only correction I would make on the above comments is that I would change the "could" make them happiest of all to "would" make them happiest of all. There really is no satisfaction quite like helping someone else along life's highway. This is true, whether the person genuinely appreciates what you've done or even comments on it, though that obviously would be the desired result. There is something inside of all of us that leads us to feel that we are being our best self when we do something for others. The old Biblical quotation that "he who would be the greatest among you must become the servant of all," is true. Give helping others a try and I'll SEE YOU AT THE TOP!