In the javascript world, user is best described as a source of random and contradictory signals. He starts one action, then another, then third (that cancels previous both).

Most widespread real-world example is autocomplete: we have to make requests based on user input, but each consequent keypress requires different request than one that is being currently done (or recently been).

Sometimes we need to search and remove several elements in a numerical Javascript Array (so we have to modify array in a loop).

I've heard this phrase a lot of times, but most of the times the client didn't really know what exactly he wants. "To create a website" isn't only the technical task as lots of people think, and it isn't a kind of magic also. First of all it is a marketing task and your website can be successfully developed when you exactly know what you want and can formulate it on the business language.