"I am bound to say that in all accounts which you have been so good as to give of my own small achievements you have habitually underrated your own abilities",
is offered by Sherlock Holmes to his assistant in crime-solving, Dr. Watson. It is a compliment to Watson's burgeoning analytical abilities, but, as it turns out, a back-handed one of sorts. Holmes is saying that Watson, who is in the habit of talking about his famous boss in glowing terms, does not often enough consider that he himself possesses strong abilities in the area of criminal investigation as well.
An anonymous visitor has come by the night before, and left a walking stick behind, apparently inadvertently. Watson is idly examining the stick when Holmes asks him to describe what he sees and to draw inferences from his observations. Watson's answers please Holmes, and it is then that Holmes offers his "compliment". Watson is pleased, but when he asks Holmes "self-importantly" if there is anything he has missed, Holmes replies that, in actually, it is ironically not because of the accuracy of Watson's conclusions but because of his errors that he (Holmes) has been "occasionally guided towards the truth". Watson's ego must be somewhat deflated when his boss points out that, in analyzing his protege's mistakes, the master himself has come to the correct conclusions!" (Chapter 1).