The number 13 has a negative image in the culture of many countries, especially Western countries. People have cited many reasons to affirm that the number 13 is a symbol of bad luck. Typically, the dark Friday the 13th or the last supper of Jesus Christ.
Another reason why the number 13 is discriminated against is because it comes after the number 12. Mathematicians always consider 12 a complete number: 12 months of the year, 12 zodiac animals, 12 zodiac signs, 12 gods on Mount Olympus, 12 apostles of Jesus Christ... And the number 13 that follows it breaks that harmony and order as if starting a new cycle.
For Eastern people, partly due to the influence of Western culture, partly due to the psychology that the number 13 brings bad luck and needs to be avoided, many people are worried when their house number, license plate number, or phone number contains the number 13.
To mark this fear, psychiatrists also came up with the term Paraskavidekatriafobiya (fear of Friday the 13th). People with this syndrome will be very afraid when hearing or seeing the number 13 and have mental symptoms such as: rapid heartbeat, shortness of breath, panic, nausea, etc.
Combining the above reasons, we can easily understand why apartment buildings do not have a 13th floor, with the aim of helping buyers feel more secure when choosing to buy apartments here, while helping the project to be completed completely, without any incidents during construction. On the other hand, even if the 13th floor is reserved, it is likely that the investor will have to reduce the price a bit or take more time to sell the apartments on this floor due to the cautious psychology of buyers.