The universal appeal of Three Men in a Boat (to say nothing of the Dog), is that of friendship and the comraderie that comes from knowing someone for a great length of time. It also points out the absurdity of some notions and excuses that people give for why they haven't achieved at the level of their own expectations. The men are on a journey, not only physically, but emotionally and psychologically. They are all tired of the way their lives have unfolded. They are to the point, some of them, that their health has begun to suffer. As the book goes on, of course, the reader sees that it is not as much a physical ailment, but an illness of the spirit. This they reclaim through the series of mishaps and misadventures that they have along the way, leading them to see what wonderful lives and loves they have.