Interesting fact - Tetraphobia in South Korea

Do you know what tetraphobia means?

Meaning of Tetraphobia (from Greek word τετράς—tetras, "four" and φόβος—phobos, "fear") is the practice of avoiding instances of the number 4. It is a superstition most common in East Asian nations. (Mainly in Korea, Japan and China)

(Below photos are taken from elevators commonly seen Korea (South Korea), you can see there are no number 4 on number pad or alphabet F instead of number 4)

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In South Korea, the number 4 sounds like "decease" and "died" (사-Sa), so the floor number 4 or room number 4 is almost always skipped in hospitals, funeral halls, and similar public buildings. In other buildings, the fourth floor is sometimes labelled "F" (Four) instead of "4" in elevators. Apartment numbers containing multiple occurrences of the number 4 (such as 404) are likely to be avoided to an extent that the value of the property is adversely affected. The national railroad, Korail, left out the locomotive number 4444 when numbering a locomotive class from 4401 upwards. Some of these combinations were considered more unlucky than the individual 4, 14 sounds like "Time to be deceased" (사망 할 시간), 44 sounds like "Died and Deceased" (사망 및 사망자)

However, number 1004( "Chon-Sa" 천사 it sounds like angel in Korean language) is one of Korean's favourite numbers, people prefer use 1004 for last digit of phone numbers or even using on SMS (text message) which mean's I am your guardian angel.