In another life, Mr. Tulliver would have made a mean blues singer with a hit song, "It’s a Puzzlin’ World." Mr. Tulliver has a couple of things he holds true in the world: the world is really confusing; Maggie is smarter than Tom; he himself is an honest man; and lawyers were created by the devil.
Points two and three seem to reinforce Mr. Tulliver’s insistence that the world is really hard to understand. After all, according to Victorian English notions, boys are supposed to be smarter than girls, so what’s the deal with Maggie? And as a self-described "honest man" (a phrase Tulliver even utters on his deathbed), it’s confusing that he should have so many problems in the world. What sort of world is it where honest people can get screwed over by evil lawyers like Wakem?
However, Mr. Tulliver’s repeated insistence that the world is puzzling is itself a little puzzling. Mr. Tulliver can come off sounding like a crackerjack philosopher at times, pondering the meaning of life and lawyers and what honest people are supposed to do in the world: "Mr. Tulliver [...] shook his head in a melancholy manner, conscious of exemplifying the truth that a perfectly sane intellect is hardly at home in this insane world" (1.3.38).
What Mr. Tulliver seems to be confused by is modern life, not just life in general. What exactly is modern life? Well, in this book we have lots of evidence of a changing and "modern" world. For example, money and social status can be lost as quickly as they can be gained.
Mr. Tulliver learns this last bit the hard way. This is a highly impersonal world of business and legal proceedings, where it doesn’t actually seem to matter if someone is an "honest man" or not. It’s no coincidence that Eliot describes lawyers and the law as a "machine." (For more discussion of this and Mr. Tulliver’s character, check out the "Society and Class Quotes.") The modern world doesn’t really care who anyone is, and Mr. Tulliver is thus hopelessly and permanently confused since he sees the world in highly personal terms. He never understands how Wakem’s actions against him cannot be personal, and he starts up a dangerous and obsessive feud accordingly.
Mr. Wakem is like the person who gets angry at the wall after he stubs his toe and ends up kicking the wall again in anger. Which makes matters worse for the toe. That might not be the best metaphor, since Mr. Tulliver isn’t really a toe, but you get our drift. Mr. Tulliver himself is a "puzzling" remnant, or leftover portion, from an old-fashioned world of personal interaction, personal feuding, and clear lines between good and evil. Forced to deal with the impersonal law and the gray areas of modern life, Mr. Tulliver cracks and becomes consumed with anger and regret. It’s no wonder that, in his illness, Mr. Tulliver lives in the past – the present is simply too "puzzling" for him.