I'm a self-diagnosed completionist and I hate the infinite scroll so much that I developed a mental habit that helps me work around it. When I visit a site with infinite scroll (e.g. YouTube or new Reddit) I immediately scroll down until the first loading spinner (e.g. by pressing the End key). At this point I stop and go back up processing the items in reverse order. This might sound silly, but it gives me a sense of completion and a natural exit point once I get back to the beginning.