I can make the perfect knife.
Well, not right now but if I put my mind to it (and enough coin) I can succeed. It may take a while starting from square one but given enough time and perseverance I really can make the perfect knife. Perfect for me at least.
But it won't be pretty. What do I mean by pretty? Have a look at one of my favorite knives, the Sakai Takayuki Syousin Sakura from KnivesAndStones:
This knife is good looking, if I do say so myself. On top of that it's an excellent performer. The knife is balanced well and has a powerful heft to it without being so heavy regular use gets unreasonably fatiguing. Not visible in the picture is a hollow grind starting at the shinogi (line straight down the middle of the blade) and terminating at a small microbevel along the edge. The core steel is Blue #2 which is clad in reactive mild steel. This knife's handle is made of Ebony and black buffalo horn with a nickle-silver spacer.
No matter how much time I spend making my "perfect" knife, I can't make something like this. This is art, and art can cost a lot. This is also just a tool and so from a distance it might seem foolish spending so much on something that is meant to be used and abused. After all, you wouldn't spend more than few bucks on a screwdriver, would you? Certainly a $100 screwdriver isn't going to dramatically outclass a $5 screwdriver, is it? What about knives? I know for sure that a $100 knife is definitely superior to a $50 knife, maybe twice as good, but a $200 knife is not often twice as good as a $100 knife. Diminishing returns and all that jazz.
So at what point do you stop and think, "am I buying a tool or am I buying a piece of art"? The turning point is going to be different for everyone and there's no right or wrong answer. Just know that at some point you're paying more for form than for function.
I'm all about practicality, but if we always gave up on form in favor of function the world would be a very dull place.