Well, I don't disagree with Steve at all, but I have a different take on this.
The purpose of life: It is to be at peace with how you lived your life, at the moment of your death.
Yes, I am aware that we may not have a moment to reflect on life right before you die -- it may come so suddenly that you probably don't know what hit you. (I'm guessing here, since I haven't experienced it yet myself.
When many people talk about "living a life you don't regret" they talk from an accomplishment-based view. You know how we often talk about things we want to do before we die.
Well, that sets a trap, as we don't know when we're going to die. To have a list of do-before-death list risks things remaining unfinished, which gets in the way of you feeling good/proud/at peace with your life. It's not about what you did in your life, it's how you live.
If you haven't done so, you better identify your core values and start living according to it
, because making decisions based on or in pursuit of anything else get you in the danger zone with life-with-regret.
I'm not saying don't compile a do-before-die list. Actually, do assemble it and aspire to check them off. But just don't make any accomplishments/achievements a part of your life's mission. Your mission is to live on the way to get there and do them.