For example, animated elements in a child's storybook enliven an impression of silliness, playfulness, and fun. Explaining complex information that may be difficult or impossible to capture on video. A sequence describing the shifting of continental land masses over millions of years is clearly impossible to capture on film, and therefore, being able to animate the process may be the only choice to visually show it. Enticing the user to try an interactive control. Some interactive documents are preprogrammed to animate selected screen elements if a certain period of inactivity has passed without any keyboard or mouse clicks, thereby attracting the user's attention.
Monochromatic pages run much faster and look much better.
The idea is to separate your site from all of the clutter out there. Web clutter is typified by freewheeling use of color, including omnipresent rainbow-hued buttons. If you get your design concept graphically right in a black and white, you're on the right track. After that, if you want to, cautiously add one or two colors. It's very hard to read test on computer screens.