These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Base Breaker: Mylo Xyloto. So far, fans have either fallen in love with the new, poppier direction or lambasted Coldplay for "going mainstream."
Viva la Vida before this, to a small extent. While most loved it, there was a sizeable minority who detested the "pretentious" direction and wanted a return to the old simple, poppy style. Oddly, these don't like Mylo Xyloto.
Internet Backdraft: "Princess of China". These three words will set off a bitch-fight for pages. It's either too mainstream for Coldplay fans, too weird for Rihanna fans, or it's blasted for not using exclusively Chinese elements in its video. Those who actually like the song and think the video is well-done are quickly drowned out and accused of not knowing "real" music.
Magnum Opus: Either A Rush of Blood to the Head or Viva La Vida or Mylo Xyloto.
Rescued from the Scrappy Heap: Many critics and general music fans only started to like the band after Viva la Vida or Death and All His Friends, and in particular the release of the single "Violet Hill".
More so with Mylo Xyloto!
Sampled Up: The riff in "Talk" (you know the one) is adapted (with permission) from the riff of "Computer Love" by electronic band Kraftwerk.
Chris Martin has admitted that "Fix You" was inspired by the Elbow song "Grace Under Pressure".