What's also fascinating is that the shapes and biochemical properties of proteins and other molecules in the cell are so finely tuned that they can be flying in

What's also fascinating is that the shapes and biochemical properties of proteins and other molecules in the cell are so finely tuned that they can be flying into each other, and still have such a high degree of specificity (e.g. proteins interacting with certain other protein domains, substrates, etc) that life actually works.