The origins of flags lies in ancient history. Originally they may have been simply decorative streamers, or perhaps ceremonial images. They were superior to many other emblems: cheap and simple to make; easy to carry and display; and attracting attention with their lifelike movement in the wind.
Flags came to symbolise variously leaders, communities, gods, merchant and craft guilds, ships, and towns. A flag often gained the same respect as was accorded to the person or thing which it represented. In battle, the loss of a flag was a severe blow. The capture of the opponents flag might be the turning point in a battle. Flags often bore religious symbols, and were used in religious as well as state occasions.
The modern national flag arose in the seventeenth century, with the creation of the first modern states. Before that most countries had only had the flag of the rulers. Some modern national flags are even now used only by the government and military, with a different flag (a civil flag) used by the people.
A flag represents an idea, or an ideal. It is neither a mere piece of decoration, nor an object to be honoured for itself. It is honoured for what it represents. Many flags are held in high esteem for their history; for the sacrifices made by the people; for the qualities for which the country and people stand.
Such respect does not depend on the aesthetic appeal of the design, or on it attempting to represent visually the people or politics of a country. If it represent anything tangible, a national flags generally symbolises the unchanging characteristics of a nation. These can include the geographical location, or perhaps a distinctive physical feature, historical foundation, or (to a lesser degree) the constitutional structure. In democracies they do not generally represent political affiliations.
https://m.youtube.com/watch?v=fqlLc4pxC7w
Respect for the flag is one indication of patriotism. Public dishonouring of the flag is regarded as an extreme form of dissent in most countries, and punished accordingly. Some countries, notably including the USA, make the public affirmation of loyalty to the flag and the country a civic duty. New Zealanders have not regularly honoured the flag in public ceremonies since the 1950’s.
To fly the national flag is a sign of pride and patriotism. It a positive affirmation of loyalty and commitment. It marks out a country that has confidence in itself, and is comfortable with its place in the world, its history and its future.
https://www.saic.edu/~hkang2/importanceofflag.htm
Blurt will certainly cover the whole world