The time in between turning the hot water knob and hot water actually coming out of the faucet depends on the technology you use to heat your water and how far away that contraption is from your bathtub. You could, move your water right beside your bathtub for the fastest response time. This is not necessarily advisable, but it serves as an example of how delays work in interconnected systems.
In fact, understanding delays is a necessarily mental tool for thinking systemically. There is a delay between the birth of the baby-boomer generation and the seismic impact that they will have on the health care system in their later years of life. There is a delay between the moment that ‘patient zero’ contracts a devastating contagion and first symptoms of outbreak in a population. There is a delay between the invention and release of an innovative app and economic disruption for established business models. There is a delay between an economic downturn and employees receiving severance packages.
The point is this: nothing that happens in a system happens to the whole system at exactly the same moment. All systemic change occurs in ‘ripples’ that take time to germinate. Revolutionary mobs are not incited overnight, but emerge as the culmination of numerous preceding factors and triggers.
Intervening in delays is virtually impossible. Unless you do all the hard infrastructure work to change buffers, you cannot really do much to leverage a delay. But that said, you must be aware of delays in order to leverage much of anything else.