For me... the easiest way to lose me is pop-ups, audio, and spammy looking ad sites.

    

Also the overall look and feel of your website is critical to offering an organized view of what you want visitors to experience. The Website design fails to keep an audience when:

* Chosen colors are annoying
* Fonts that do not stand out
* Too much material
* Broken links
* Navigation is difficult

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Ecommerce SEO :: Are you looking for Web Hosting

Most visitor won't stay if your loading time is to slow, you got it right mate. that is why google is creating google caffeine.

Adding to your points
1.Too much content,cluttered and crowding the page
2.Cheeky color theme (Very few people like such sites)
3.Non working buttons on the page
4.Latest updates dated last year !
5.You filled up a form and clicked 'ok' or 'submit' and the form gets deleted asking you fill it all over again.

1. sssssslllllllloooooowwwwww loading.
2. It's not what I'm looking for. Most website I find via search, I leave after about 3 seconds... I guess I'm not very patient.

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http://www.tradeshowninja.com

could be anything...sometime, we just dont find what we are looking 4 or more than what we need..so we exit

There are two to three reasons thats why visitors go away and from that first one is the bored content and second one is the theme of your site.......

I think a slew reasons contribute to that, and least of it is the design. Though design is important most viewers are willing to forgive a badly designed site if the content and premise of it is good and it has what they are looking for.
Some of the other reasons also include very slow loading, too many ads and pop ups, spam, irrelevant and self-serving content, wayward navigation etc.

Content..because people come to our site just to gain information they need.

Boring material...