National Good Buddy Day is observed in the United States on October 4th, inspired by the phrase "10-4 Good Buddy," which became popular with the rise of CB radios among truckers and drivers. This day celebrates the camaraderie and connections formed through this communication method. Originally declared as 10-4 Day by President Jimmy Carter, it was revived in 2004 as National Good Buddy Day to focus more on celebrating friendships. Typical customs include reaching out to friends through calls or messages, and some may even try using a CB radio to connect in a nostalgic way. The day encourages people to appreciate their good buddies and share fond memories.