
1) democracy, as Weber identified, is in tension with the logic of bureaucracy. While bureaucratic specialization is promoted in favor of administrative efficiency, it can also subvert popular aspects of rule and legitimation. For example, NSA overreach.
2) democracy can be defined both by its formalistic and more substantive attributes. These include political rituals of voting ("kick the bastards out in four years"), or it can include deeper aspects such as popular participation through mechanisms of local government.
3) democracy can either be centralized or decentralized, but proponents of either system will often argue that their opponents are abusing democracy. The famous case of course is the federalists v. anti-federalists, though non or someone with more knowledge on US history would have to comment.
4) democracy is a political discourse, meaning beyond its actual formal characteristics as a system, it's a more general language through which people articulate ideas about how society should become "better." It's associated with equally vague notions such as "justice" and "freedom" that are colored by their historical association with particular groups, classes, or political parties. Among the Left for example Bush managed to turn democracy into a dirty word, a mere propaganda trick, given its association with the project to "liberate" Iraq and other third world countries.