The use of 等一等 (děng yī děng) highlights a subtle but important aspect of Chinese communication: the preference for softening commands to maintain social harmony. In English, shouting “Wait!” can be perceived as rude depending on the tone. Similarly, in Chinese, just saying the verb 等 (děng)! is very abrupt and often impolite. By adding 一等, the speaker transforms a direct order into a gentle, polite request. This structure is less about a deep philosophical value and more about daily conversational etiquette. Compared to Western directness, this softening is a form of conversational lubricant. It's similar to how an English speaker might choose “Could you hold on for just a second?” over “Don't go.” It ensures the interaction remains smooth and considerate, even when making a request. This politeness is a small but constant feature of everyday social interactions in China.
等一等 is extremely common in all sorts of informal and semi-formal situations.
The connotation is almost always neutral to positive, as it's inherently a polite-making structure.