I guess the point I'm getting at is, at what point do you say “I’m done with this” and click on the back button. Is it something in particular that makes you decide to move on? I'd be interested to see what you're reasons are. My main reason would be if the website isn't loading. I'm a patient person but if I have to sit there longer than 20 seconds (10 seconds more than most people), I'm clicking the back button. No questions asked. How about you?
I generally skim websites. When I decide to click off is completely dependent on what is I'm looking for and if the site has it in part, full, or neither. I'm done when I've gotten my fill or lack thereof.
When I find the answer I am looking for, I leave. I am busy and have no time to spend minutes or hours browsing multiple pages on a website I do not need to view. Some people think a high bounce rate is a bad sign. It could be, but it could also be that the landing page had exactly what the surfer was looking for and they needed to look no further. So a high bounce rate could be a sign you have good content as well.
I think the main thing that makes me leave WITHOUT READING ANYTHING is when videos start up with load music on there own. They are horrible and make me mad! On the other hand in general it depends what I am looking for and the other big reason for leaving is that the site is taking too long to load or if their graphics are not showing.