You put your foot on the accelerator. The car goes into a furious, uncontrollable, clockwise spin. No, This doesn't happen in car showrooms. But it does on Web pages. Clue' is the important word here.
Interface design is all about visual clues.
When Web pages first appeared a few years ago, the mechanisms for navigation were well thought out. A 'hot' word with a link behind it would be immediately identified because it was underlined and in a different colour from the rest of the text. Clicking on the word changed its colour to give the reader confirmation that something was about to happen, and then teleported them to some relevant text elsewhere. On returning to that page, the hypertext link had changed to a third colour to show that it had been previously visited. Instead of being an obviously clickable button with user feedback clues, it becomes a static picture of indefinable function.