Unchallenging music is music that requires no effort to play or perform.
Generally, music that are riddled with synths and drum machines are unchallenging. Take R&B/Pop artists for example, they are basically just singers to a pre-programmed backing track.
When Madonna went techno with her Ray Of Light, how much of her music was actually created by her? How much of the electronic beats were programmed by her? Most likely she just sang the song.
A challenging song challenges not only the artist but also the listener. When you put some pre-programmed jungle bass sounds that isn't even hand played, add a double tracked drum track the sprinkle it with you best 2LiveCrew impersonation with lyrics like "mother fucking, sugar shopping rock and roll" - then you get a very unchallenging song.
Put a drum loop, no instruments and just sing "Miami my mami" then you don't get a challenging song. For U2, their challenging songs let all the band members use their full potential.
That is why I think POP is U2's most unchallenging album to date. I can't blame them for not being up to the challenge - they were pressed for time.
Take a song like Stuck In A Moment. It challenges the listener to reconcile a seemingly uplifting melody with the concept of suicide. The lyrics, the message, the melody and the music all seem to contradict. The band created this challenge for themselves and for the listeners.
Vertigo is another challenging track. Mullen has to play into breakneck tempo like he has never played since the 80's, while Edge plays the guitar as if his fingers will bleed. Clayton has the groove moving up and down, while Bono is singing pre-90s Bono trying to convince the listener "I can feeeel".
How To Dismantle An Atomic Bomb is full of challenging music, unlike the challenge-deficient POP. The band challenged themselves to play at a different level, and the listeners were challenged to try to absorb what they were up to. We now live in a world where people love challenge. The world of reality TV shows, and Fear Factor dares. Challenge is something that fascinates everyone now. And U2 intentionally made challenging music with HTDAAB to give the audience something to attempt to "conquer" or "understand" or whatever else you call it. If unchallenging U2 music like POP was released today, it probably wouldn't even reach platinum. Do the Chemical Brothers and Prodigy still sell today? No because they bore the listeners by not playing real challenging hand played music. It sure is easy to make music from one's laptop. Little challenge involved especially the new music effects and music make software that is idiot proof.
Cheers,
J