Yeah, I can't stand infinite scroll pages. It becomes impossible to pass a link to someone to a specific section of entries. It generally breaks the back button -- when I click a link and then go back to an infinite scroll page, it has dropped all the dynamic content and has to reload it, and then I have to scroll back to where I was (which may have involved several minutes of scrolling and loading content).
Perhaps it's irrational, but it also frustrates me that such pages have no bottom. I think people got used to a model of a page where it has a top and a bottom, and now it's a bit weird to interact with. One of my favorite examples is Facebook's implementation, which leaves several useful navigation links in the page footer. These links taunt you as you tried to scroll to reach them, only to have more news content appear in your view and push the footer off screen again. (I think they've since duplicated those footer links in other locations so you can reach them, but it doesn't change the fact that this broken UI model presents options and then sucks them away before you can click on them.)
Infinite scroll pages are harder to read with a pointing device withouth a scroll wheel, because the scroll bar jumps randomly when reaching the bottom.
Perhaps it's irrational, but it also frustrates me that such pages have no bottom. I think people got used to a model of a page where it has a top and a bottom, and now it's a bit weird to interact with. One of my favorite examples is Facebook's implementation, which leaves several useful navigation links in the page footer. These links taunt you as you tried to scroll to reach them, only to have more news content appear in your view and push the footer off screen again. (I think they've since duplicated those footer links in other locations so you can reach them, but it doesn't change the fact that this broken UI model presents options and then sucks them away before you can click on them.)