If you tend to think all top 40 music sounds the same, there are reasons for that. And one of the biggest is what product manager and musician Patrick Metzger recently dubbed “the Millennial Whoop”, a repeated alternating series of the 5th and 3rd notes in a major scale. It’s currently all over the radio and it probably won’t be going away any time soon.
Songwriters have begun incorporating tropes like this and the ubiquitous “hey!” into songs because they know they are already familiar to the listener from other hit songs, and that bit of familiarity helps to make said listener comfortable with the new song. It’s like a musical referral of sorts–the stranger who’s introduced to you by a friend.