In Connectome there is an interesting point about how the Golgi stain did not stain all cells so that it is possible to see the ones it stains in the very busy landscape of many cells. Sebastian Yeung in Connectome used the example of staining one strand of spaghetti in a bowl of many and we can, even with blurred vision, make out the stained spaghetti.
This relates to HCI maybe as a principle of not showing too much when our focus is not sharp.