the institutions that encompass many the other institutions, both formal and informal (e.g. the family, government, the economy, education, and religion.) Most important institutions, considered abstractly, have both objective and subjective aspects: examples include money and marriage. The institution of money encompasses many formal organizations, including banks and government treasury departments and stock exchanges, which may be termed, "institutions", as well as subjective experiences, which guide people in their pursuit of personal well-being. Powerful institutions are able to imbue a paper currency with certain value, and to induce millions into production and trade in pursuit of economic ends abstractly denominated in that currency's units. The subjective experience of money is so pervasive and persuasive that economists talk of the "money illusion" and try to disabuse their students of it, in preparation for learning economic analysis Informal institutions have been largely overlooked in the comparative politics, but in many countries it is the informal institutions and rules that govern the political landscape. To understand the political behaviour in a country it is important to look at how that behaviour is enabled or constrained by informal institutions, and how this affects how formal institutions are run. For example, if there are high levels of extrajudicial killings in a country, it might be that while it is prohibited by the state the police are actually enabled to carry out such killings and informally encouraged to prop up an inefficient formal state police institution. An informal institution tends to have socially shared rules, which are unwritten and yet are often known by all inhabitants of a certain country, as such they are often referred to as being an inherent part of the culture of a given country. Informal practices are often referred to as "cultural", for example clientelism or corruption is sometimes stated as a part of the political culture in a certain place, but an informal institution itself is not cultural, it may be shaped by culture or behaviour of a given political landscape, but they should be looked at in the same way as formal institutions to understand their role in a given country. Informal institutions might be particularly used to pursue a political agenda, or a course of action that might not be publicly popular, or even legal, and can be seen as an effective way of making up for lack of efficiency in a formal institution. For example, in countries where formal institutions are particularly inefficient, an informal institution may be the most cost effective way of actually carrying out a given task, and this ensures that there is little pressure on the formal institutions to become more efficient. The relationship between formal and informal institutions is often closely aligned and informal institutions step in to prop up inefficient institutions. However, because they do not have a centre, which directs and coordinates their actions, changing informal institutions is a slow and lengthy process. It is as such important to look at any given country and note the presence of informal institutions when looking at the political landscape, and note that they are not necessarily a rejection of the state, but an integral part of it and broadening the scope of the role of the state in a given country.