Perhaps the same thought nags at you as well.
I prefer answers that are simple and direct, and don't require invoking a cosmological constant. It wasn't until later in life that I came up with an answer that works for me.
Your results may be different, naturally.
I believe it's very simple: we are here to be happy -- individually and collectively.
Learning To Be Happy
I think it has something to do with hormones.
As an adult, I was eventually successful in teaching myself what made me happy. It wasn't obvious at first. I lost a lot of time chasing things that other people told me were supposed to make me happy, but didn't. My world changed significantly for the better when I finally dialed in the working formula.
A key learning: listen to yourself, not others.
I often meet adults of all ages and all walks of life that haven't succeeded at this fundamental mission yet. I feel for them, and help as I can. May you have an epiphany as I did.
When you're happy, you tend to live a harmonious life. You don't quarrel, or have many bad days. You aren't easily irritated, and you don't rant much. Your energy and interactions tend to be positive, which engenders the same from others. People want to interact with you as a result.
And, most importantly, being happy at your core enables you to do more for others.
Helping Those Close To You To Be Happy
Like many of you, I am in a long-term married relationship with three wonderful kids. I really, really want them to be happy, much as I am. I work hard at helping them as needed, but it's fundamentally their job -- not mine.
My wife is very happy these days. She is doing exactly what she wants to do, and is quite good at it. Her days are long, but she enjoys it deeply. Seeing her so satisfied of course makes me happy.
Yes, it sounds dopey, but it's true -- you can't be happy unless your spouse/partner is happy as well. I have no problem putting her happiness ahead of mine as need be.
My three children are all happy young adults. They feel good about themselves, their place in life, and what the future will bring them. As a result, they tend to make good decisions, which is important.
Seeing them on the road to their future makes me deeply pleased.
Helping Others Be Happy
Once you've taken care of yourself and those close to you, you're in a stronger position to help others. I've found that's very hard to do if you're worrying about your own situation, or that of your family.
For example, I routinely make the time to encourage and mentor those that I work with. Skip the corporate mentoring program, and just do it because it feels good to help others. Most of the time, I help people discover what they really want out of work and their career. Often, they've adopted someone else's goals without going through their own internal discovery process. That's sort of like wearing someone else's clothes and expecting to be comfortable.
I give of my time and money. If someone I've met is going through a rough patch, I listen with empathy, offer encouragement and refrain from giving specific advice unless asked. When I retire, I look forward to investing more time in younger people going through their formative years -- it can be a rough patch for many.
Not everyone means well. If someone appears intent on putting a dent in my positive attitude, I steer clear and refrain from interaction. Lots of people out there working on lots of issues, and not all of them can be helped.
A Simple Philosophy
Thinking about the world this way makes it very easy in my interactions with others: I try to help them get what they want unless it would adversely impact someone. Happiness shouldn't be a zero sum game. When I can help someone out, I feel good -- it's a win-win.
So, what's your philosophy?