When people tell me something like that, I start asking questions about what they want. It only takes one or two questions to evoke a reply from them of, "Oh, I don't know... maybe it should do this, or maybe it should do that; it kind of depends..."
And therein lies the real problem. When the end user cannot even clearly define (or even decide!) what they want when a certain situation comes up, how could a computer possibly know? Put the user next to a good developer, and I promise the bottleneck will be the user.