- Mouse droppings. As annoying as pop-up ads — and the only way to get rid of them is to leave the site.
- Mystery meat navigation. Your visitors should never have to guess where to click.
- Transition effects.
- Java plugins or applets. These things are guaranteed to crash somebody’s browser, even if they work in yours.
- Sounds that play automatically. I’m quite happy with my internet radio; the last thing I need is some lame typewriter sound effect interrupting me.
All this crap takes lots of extra time to implement, anyway. Just say no.