Do you imagine ancient scribes cheerfully copying texts? Think again. IO9 highlighted some of the more amusing comments from some medieval manuscripts, including more profound ones such as “As the harbor is welcome to the sailor, so is the last line to the scribe” and more succinct ones such as “Oh, my hand!”
How impoverished is the perspective of those of us who work with printed critical editions, which don’t as a rule indicate the marginal comments of scribes unless they are relevant to the matter of the text itself. And they never include the doodles.