Rather than being UNDERrated, to me it's very overrated. The album starts off very strong, the first four or five songs being excellent. Then the album takes a huge nosedive with The Word.
Rubber Soul is probably the album with the most tracks that I skip of any Beatles album, I feel like half of the album is filler. I've never cared for Michelle or Girl, they're both border on insuffeerable to me. I usually skip The Word, What Goes On, Wait, and Run for Your Life.
Basically, I like the first five songs, I'm Looking Through You, In My Life, and If I Needed Someone.
I know I'm in the vast, vast minority on this one too. To Me, BFS, Help, and Revolver are far superior to RS and BFS and Help are underrated.