Animation
Unless you are designing for a very young audience, excessive animation can be distracting.
Even if the main feature of your site is animated content, you want to keep in mind that animated elements draw the eye, and multiple animated elements on the same page could compete for the viewer's attention.
When considering the use of animation in your design, keep in mind that many banner ads are animated. Adding more animation can be annoying to the audience, and it can even slow the responsiveness of your site on older computers.