I have an entrepreneur friend who used to carry a butter knife around. He claimed this almighty tool was the only one he ever needed! While the butter knife does serve a wide range of purposes (especially with a stretch of the imagination), in practice it doesnt always yield optimal results. For example, as a screwdriver, it may work for common screws, but certainly not a Phillips (unless you push down very hard and hope not to strip the screw). As a hammer, you may be able to drive finishing nails, but your success and mileage may vary. As a pry bar, well, I think you get my point! Clearly one tool isnt sufficient for all purposes a good toolbox includes various tools each fulfilling a specific purpose.