To create a pleasant, positive atmosphere for their waiting callers, pop music with light electronic sounds is suitable. Light jazz notes are also often found. Especially Lounge or Easy-Listening Music is suitable for queues.
The particular song should be easy and and innocuous. It is important that the song does not become unpleasant even during longer waiting times. If song passages repeat too often, the listener will get bored faster.
The main purpose of the music piece is to put the caller in a positive and patient mood. After all, nobody likes to wait in a waiting loop.