I'm always trying to hit perfect. Not that I think it's actually achievable, but that it's the approximate goal. Part of the thing is that when I design it in CAD the result is perfect, and that perfection feels really good. But transitioning from the screen into real physical form is where all the challenges lie. It's not enough to design something great on the screen, it really is only worth something if it can be built in the real world.
Back before I had a CNC that possibility seemed further away. Building furniture with conventional tools like table saws and drill presses, and joiners etc requires very careful setup and measuring. I was often frustrated by the combination of my own physical lack of skill and the lower quality tools I was using. In that era, designing on the computer was almost unnecessary because what I could produce wouldn't really match it.
Now, with a CNC the results are much closer. But they're not perfect. There are a lot of factors which can contribute toward results that don't match my intent. Tolerance comes in. The machine doesn't always cut exactly what I want. Sometimes it's my programming fault, sometimes it's other environmental factors or mechanical factors which result in parts that are slightly off.
I just got a load of plywood which measures .02 thicker than what it usually is. This has caused a lot of problems. Parts fit too tight, lots of extra sanding. Annoyed, I looked up the plywood spec and found that the amount was actually inside the allowable tolerance. Now I'm making new programs which work with thicker stock so when I measure the stock I can choose which program to run. It's not as in the 3D print world, or even metal machining world. Wood has variation, it comes from living trees, and so I have to constantly adapt to it depending on how much moisture content the wood has.
It's important to remember that despite all of the challenges of working with an ever changing medium, the wonderful thing is that each piece is different. No two nightstands are the same, because the wood pattern and variety is always interesting and different. It's those differences that make each piece special, and assembling each is enjoyable to me as I meet the challenges and changes they present. That's all for now.