I remember at the time hearing stories of legacy systems that were in a dreadful state and in one case still using microfiche as part of the day to day processing.

I know some time has passed since and a lot of money and effort has been spent in improving things but I'm still pretty impressed just how quick it all works. My banking app notifies me when money is sent or received from my account and it usually beats the checkout confirmation page load time or POS approved message when I make a purchase.