I would like to add two more thoughts if you like. I design houses for a living and once in awhile, after looking back over my design, I think of things I could have done better. But I also have come to realize that I did the best I could at the time and only in retrospect do I see a "better way." I think it is good to look at things in retrospect for a moment, but at the same time, to realize our limitations. We aren't God. I mean, we don't have the ability to know, in advance, which course of action will turn out for the "better." I think God want's me to take stock of my limitations and to embrace them as my personal truth. God has given me the gift of rational thought, which allows me to see "the better" in retrospect. But being a limited creature, I can't always know "the better" in advance.
Second, over time I have come to embrace a particular mental attitude that seems appropriate, which is found in the New Testament.
Colossians 3:23-24
Whatever you do, do your work heartily, as for the Lord rather than for men, knowing that from the Lord you will receive the reward of the inheritance. It is the Lord Christ whom you serve.
When I draw a house plan for someone, I realize my primary client is the home owner. But as I do the work, I remember Paul's words to do my work heartily as for the Lord rather than for men. This attitude helps me do my best for everyone.