Scientists asked what makes a song catchy? That is, what makes a musical combination stick into our memory, plug itself into our brains even if we dislike the song?
No definite answer but a combination of: familiarity (similarity to music we already know), cultural connection, repetition both in listening (like hearing it over and over on the radio) and in having the chorus (or some short part of the song) repeat over and over, as well as a particularly appealing performance.
Don't ask me how but sexy songs induce larger Canary eggs:
A new study reveals that female songbirds alter the size of their eggs, and possibly their chicks' sex, in response to hearing a sexy song from a male.