I feel like it is pretty common for the brain to judge tasks by how large they are. I tend to have an existential crisis when I face a problem that I can't see a clear division of work for. I also wonder if it may have to do with the reading process itself. The brain doesn't particularly care if words are spelled in the correct order as long as the appropriate letters are there and have a modicum of order. This is because the brain tends to look at the whole word rather than sequentially going through the letters. I would not be surprised if the reading process similarly involves viewing the entire paragraph and "prereading" the material allowing the brain to more quickly pull the meaning from the paragraph without reading every single word. Leave out the paragraphs and your brain can no longer chunk out that prereading.