I took about 20 hours of Economics before I switched to Geography for my undergraduate degree. Not only because reading Toynbee and Mackinder is downright riveting compared to Keynes and Hayek, but because I started to get the feeling that the whole subject of economics is a house of cards. It's a bunch of models, which are only useful if tied to reality, but the assumptions economists make to build their models are based on half-baked, or outright false, theories of human behavior.
Take the idea of the Rational Actor. Economists presume that human beings act rationally and all those thousands of small rational decisions and choices create unbeatable efficiencies in the marketplace. Now, by using the word rational, they mean simply that people weigh cost against benefit before taking an action. But they never address the fact that people often do not act rationally, even in this limited sense. People are social, emotional, hormonal, impressionable, tribal, and so much more, but rarely, oh so rarely, rational.
The American Scientist has a well-developed discussion of the problems with the rational actor theory in the context of game theory and other developments in the behavioral sciences. In the vein of E.O. Wilson's idea of consilience - where he suggests that the hard physical sciences and the life sciences need to converge their fields of study, so should Economists and other behavioral scinces, such as Psychology and Sociology, so we can gain greater insight into what is actually happening in the marketplace.