One customer asked if we could please speed up his data download. He had clicked and was waiting for a CSV file of all his Open Day bookings to download in his browser. It was taking ages.
Over lunch, one of our Devs took a look at the code that builds the data files. After speeding it up he sent it over to Customer Support for testing. It passed and was released. A whole bug fix lifecycle of just 4 hours.
We reduced the delay from 16.02 seconds to a mere 664 milliseconds. So now there is no wait. It is virtually instant. And the change went live this afternoon.