Rich said a lot, the most important being that if one doesn’t hear "it", then one doesn’t hear it. Two who DID hear it in the music of Brian Wilson were Paul McCartney and Leonard Bernstein. Paul proclaimed Pet Sounds the best album ever made at the time of it’s 1966 release, and was his inspiration for Rubber Soul---an album with no filler songs. If a listener doesn’t hear something very, very special in "God Only Knows" (which I consider the "best" song I have ever heard), I am at a complete loss as to what to say to that listener. Bernstein made "Surfs Up" (a song to be included in the then-upcoming Beach Boys album Smile; the album was ultimately shelved, and remained unreleased for four and a half decades! Smile acquired legendary status over the years, and was eventually released as a 6-CD boxset. The complete album was also performed live in a single performance at London’s Royal Albert Hall, people coming from all over the world to hear it. Paul was there.) the centerpiece of his 1967 television special on the then emerging newly sophisticated music from the Pop/Rock field. The special included a film of Wilson playing the song unaccompanied on the grand piano in his living room. You may want to see it, and in fact the whole special.
There is video on YouTube of a music professor sitting at a piano, breaking down "God Only Knows", explaining and demonstrating the extremely sophisticated compositional skill it’s writing required and reveals. Of course, that doesn’t necessarily mean the song will therefore be liked by all who hear it, but the video may help those who don’t particularly like the song (how that can possibly be the case is a complete mystery to me, but...) to understand and appreciate why others do. I truly feel sorry for anyone not utterly devastated by "God Only Knows". It’s an absolute masterpiece.