Many have observed that House, M.D. is a version of Sherlock Holmes, but this episode shows how well it is conceived. At some point of the show the patient gets very mad about what the staff is doing. It seems to be an insignificant detail which has nothing to do with the illness, but it is, indeed, a side effect of the underlying problem (no spoiler here!). So it is a small piece of evidence (although unused in the plot). It shows how well informed the authors are and that a lot of clues are laid out for the spectators to guess what is going on.