Often when I arrive at a content page online, I read the first few lines and find the answer or information I was looking for. Or I at least get the gist of it. I then stop reading and hit the back button.
In other words, the writer has revealed the good stuff at the top of the page, and has given me little or no reason to keep reading.
In fact, I have made the same error with this post. You have already finished reading the short version of what I plan to say and – if you were in a hurry – you could pretty much move on at this point.
(That said, the good stuff is yet to come…I just didn’t flag it in the intro.)