All tagged i dont know why meaning

What does "I Don't Know Why" by Imagine Dragons means?

"I Don't Know Why" is the first song from Imagine Dragons's new album Evolve. It might be one of the poppiest songs we've ever heard from them (at least until you listen to "Start Over" which goes so far as to adopt a Justin Bieber jungle beat). "I Don't Know Why" only goes so far as to be a pulsing, pumping pop rock smasher that reminds me more of Demi Lovato or Maroon 5. The song is intense, sexy, and lyrically focused on dangerous love.