The burrito you might decide to eat at a local Mexican fast food restaurant might not have that much in common with some other Mexican restaurants, especially those located in Mexico itself like Leon restaurants or restaurants on the Baja Peninsula. A variety of spices and ingredients define Mexican food, but depending on the location and style in which a chef has learned to cook, some of the dishes might appear quite different from something at, for example, Taco bell.  It's likely that the only commonality between some Mexican styles is the usage of corn and beans which are both Mexican staples.