Everything is hard on a world-class level. Even programming and Math is hard on a world-class level. Writing 3D engines like John Carmack does is hard. Solving million dollar math problems, or coming up with unexpected theories is very-very hard. Creating a natural language translation system, a speech recognition system is hard. Winning the Netflix prize is hard. Programming the same kind of relatively simple webapp over and over again is probably easy; and I agree that compared to that understanding what the customer wants is usually much harder.