Socrates defines piety as gratitude for an unpayable debt. He points out that we all owe our existence to our parents, and therefore we owe them something; in parallel, we also owe debts to the state and to the gods.
When I look at my own existence, relative to the incredible vastness of the universe, I feel dwarfed. I'm tiny. I didn't have to exist at all, and it took an incalculable confluence of causes to bring me into existence. If one tiny thing in the whole universe were different, I might not have been.
This seems to me a very important thing to reflect on. In the Bible, the book of Job touches on this:
"Where were you when I laid the foundation of the earth?
Tell me, if you have understanding.
Who determined its measurements--surely you know!
Or who stretched the line upon it?
On what were its bases sunk,
or who laid its cornerstone,
when the morning starts sang together,
and all the sons of God shouted for joy?" Job 38:4-7
It's a reminder that we weren't there at our creation. Even if it were possible to know everything about the universe, we still have to face the reality that we did not create ourselves. We owe a debt to whatever did -- a debt which can't ever be repaid, because we can't create our creator in turn.
To me it seems clear that we ought to worship our creator -- even if you happen to believe that your creator is a vast, unconscious universe that can't hear you. Simply on the grounds that you are a conscious, moral being, you have to accept a debt of gratitude to the universe, because if any debt exists, this one surely does. And I believe it changes you, in a good way, to worship. It teaches you not to be too proud, too sure of yourself, too ungrateful. It teaches you to see the universe as a gift.
If I didn't believe in God, I would worship nature, just because it makes sense to me to worship something. Someone with a healthy respect for nature -- understanding it as an infinitely complex, interdependent system -- isn't going to try to remake nature without hesitation. They wouldn't genetically modify organisms without asking questions like "can we prove these are safe?" and "what happens if these get loose into the surrounding ecosystem?" They wouldn't cut a tree without asking, "Can the forest replace the tree I'm cutting?" They wouldn't take an antibiotic without asking, "What effect will this have on my microbiome, and is there a real need to do this? Will this create resistant bacteria?" Not that we should never splice a gene, cut a tree, or take an antibiotic -- but that we should try, as best we can, to calculate the possible results beforehand. Nature is not simple; don't ever assume you understand it all.
I guess what I'm recommending is humble mindfulness toward nature. Coupled with this is the understanding that we are one link in a vast chain -- the generation alive today received the earth from the generations that came before, and we want to hand it on to the next generation better than we found it. What selfishness it would be to say (as some do) "the problems resulting from my action won't kick in until after I'm dead." Your ancestors left something of the earth left for you; leave something for your descendants.
Likewise (it occurred to me the other day) we ought to have a similar respect for culture. Culture is also vast and difficult to understand. Only in retrospect can we see that over-irrigating Mesopotamia was the downfall of at least one civilization, that the invention of the heavy plow led to a population boom, that discovering the New World led to the deaths of thousands from smallpox and other diseases. So we should look to the past and learn from it, and weigh our actions against their possible results.
That isn't to say we should never attempt to change either nature or culture. G. K. Chesterton says that when we see something we don't see the point of, we should leave it alone until we do. So if you see a gate across a road, you shouldn't say "I don't see the point of it, clear it away," because it might be keeping the cows in their pasture. First find out why the gate was there, and you may find that reason no longer applies and you should clear it away. But if there is a gate there, at some point someone had a reason for building it -- it should be presumed necessary until you find out it isn't.
In the same way, culture is a constantly evolving thing, and those aspects which last are usually adaptive in some way. For instance, a stigma on extra-marital sex existed to make sure that all children had parents to take care of them. Before throwing it out, maybe ask if we've come up with another solution to that problem yet, or if continence outside of marriage really is the best system available. Or popular piety -- "superstition," as I often call it, because some of it is quite irrational -- is it possible that it works on a part of our mind that is less logical, and thus binds us to our moral code more firmly than rational arguments could?
If you know why these things exist and think you would manage better without them, be my guest. But until you understand the complex interrelations of nature, culture, and your own mind (an inner space fully as ineffable as nature itself), perhaps it's best to be a little humble and accept what you've got.
This is one of the reasons why I continue to practice even parts of the Catholic Faith I don't fully understand. The Catholic Church is an extremely fit adaptation to humanity and the world, by the mere fact that it is so popular (and it very well might be so well-adapted because it was designed, I am not trying to dispute that) and it might be well to ask, why does it work so well?
While I contemplate this question, it seems a very reasonable conclusion to stick with it. Because deep in my being I have a very strong sense that it is wrong to break what you don't understand.