The sum of the parts
Most things are made from different components. You might not notice this and look at things for what they can do for you or how they make you feel. Nothing strange about that. It is actually the sign of a good design.
When design is careful, things appear to have an inherent unity that distracts you from considering the individual parts. Parts that, through their connection and common purpose, transcend into becoming new objects.
Of course you can see that a diamond ring has a stone and a gold band. However, in a well thought out design you will not pay too much attention to the platinum setting that holds the precious sparkling gemstone securely in place.
Escapes your notice
And so it is with a chair that is right for you. It provides comfort and is strong, it does not wobble and is devoid of sharp edges, it is just right. So although the maker has considered many details along the way, ultimately it is only the sum of the parts that impresses you. And at the same time, if they collectively fulfil the goal of suitable seating, you are unlikely to give them a second thought.
If all these parts are not created and made carefully considering the qualities and requirements of the other parts around them, the whole design can suffer. Not all parts are created equal, but they need an equality in a design if it is to work.
Our world is full of interlocking systems and components, invented by people to make our lives simpler and less fatiguing. Like the cogs in a clock. It is the sum of the parts that allow things to work . On their own, cogs are just spikey circles. Interesting in appearance but without being part of a greater whole they are about as useful as tree decorations. So now you have been reminded that they are everywhere, you are more likely to notice some of the parts.