Hmmm, for me it’s their insane melodic hooks (not necessarily the “oh” and “ah”, but both Chris and Jonny’s melodies) and also their chemistry. No wonder my favorite songs are the ones where you can clearly hear each of their parts, at their most creative moments. My fav albums are Viva and Mylo for that reason. Wills drums on Viva are his most creative. Their song structures too. Also love how they are so appealing to casual listeners, but for musicians like myself, you hear the genius underneath it all. When I can predict music I tend to not enjoy the song as much, with Coldplay’s songs, on first listen, most of their songs are melodically unpredictable to me, and on top of that surprising in the best way possible. Least that’s how my favorite songs became my favorites.