In earlier days of internet i.e. pre broadband days, website response issue was avery important factor. It was so critical that the websites were designed keeping response time in mind. It was recommended to keep images small and have as little flash as possible. But those days are long over gone.
But users even now CARE about website’s response time. Users even more fret about the sites been too slow. And website response time is very critical because of 2 reasons
a) Human limitations : Human memory and attention is fickle. Humans don’t perform well if they have to wait and suffer the inevitable decay of information stored in short-term memory.
b) Human aspirations: Humans like to feel in control and not wait endlessly for website to load. Companies which make us wait instead of providing responsive service are perceived as arrogant or incompetent.