The essence of a Web site is self-service.
There are three core things that self-service needs to get right: convenience, speed, and price. Convenience means task achievement with minimum effort. Speed means that you get in and out of a Web site as quickly as possible. Price means… people are cheap on the Web.
It's hard to design for self-service. It requires an absolute focus on simplicity and clarity of message. People read on the Web like they read motorway signs. They are moving with some speed.
There is precious little time to focus, so the message must be clear.
It's not enough that your Web site is a little more convenient. Your visitors are bringing a lifetime of habits with them. What they need to do at your Web site, they have done manually before.
They have received help from someone to complete this task. Now they are on their own. They don't like that.
The deeply ingrained habit inside them is saying, “This is too much hassle. Let's do it the way we always do it. Let's do it the way we know.” That is a compelling message. So to win this person over, it isn't sufficient that your Web site is a little more convenient. It has to be a lot more convenient.
If there were a convenience meter, I would say that most Web sites would struggle to achieve 40% on its scale. There is so much room for improvement. That's understandable.