All will readily admit that a first impression, however striking, is weakened when followed by an immediate repetition. Would ever a poet think of repeating half of his poem; a dramatist a whole act; a novelist a whole chapter? Such a proposition would be at once rejected as childish. Why should it be otherwise with music?
Ferdinand Praeger on the Fallacy of the repetition of parts in the classical form
Repetition is not only exhibited in lyrics or hooks it is also very evident in the composition. Take any hit pop song from the past 20 years and if you listen carefully enough you will notice a repetition on a 4 Chord cycle in almost all the songs.
Now i am in no was a master in music composition but i have spent a lot of time around musicians and paying a lot of attention to all the music i listen to notice this.
Repetition is one of the reasons we enjoy music. Repetition helps the ear and mind to understand the singer’s intent. We can see how this can be very important in a piece of music with different styles of music.
Lyrical repetition can be identified through a song that repeats the same words and melody while changing minor chords over it,
Fun repetition is when there are multiple instances of the same measures used throughout a piece. Each time these measures are repeated they may be different, but all key points will remain true to the original. For example, an ABA section regularly consists of chords I-IV-V-I with some variation between all three keys (A minor, G major and C major).
Anticipation occurs when we know a phrase will come soon before it actually does. This results in an increase to our emotions as we wait for the phrase to end.