The most expensive countries in 2023 have a number of factors in common, that make them so expensive, including:

High salaries: The average salary in these countries is typically much higher than in other parts of the world. This means that people have more money to spend, which drives up prices.
High taxes: Taxes are also typically higher in these countries, which contributes to the high cost of living.
Limited space: Many of these countries are small and densely populated, which limits the amount of land available for development. This drives up the cost of housing and other goods and services.
High demand: These countries are also popular tourist destinations, which drives up demand for goods and services. This can also lead to higher prices.

In addition to these factors, the high cost of living in these countries is also due to their strong economies and high standards of living. These countries are home to many multinational corporations and/or financial institutions, which contribute to their economic prosperity. The high standards of living in these countries are also a result of their strong economies and high levels of education.

The most expensive countries as at April / May / June 2023 are:

Hong Kong: Hong Kong is a major financial and trading hub, and its economy is one of the strongest in the world. The city is also home to a large number of wealthy people, which drives up prices.
Cayman Islands: The Cayman Islands is a tax haven, which means that businesses and individuals can avoid paying taxes on their income. This attracts a lot of wealthy people and businesses to the islands, which drives up prices.
Singapore: Singapore is a small city-state with a very high population density. This limits the amount of land available for development, which drives up the cost of housing and other goods and services. Singapore also has a strong economy and high standards of living, which contribute to its high cost of living.