My husband and I overlap in our feelings about many books--we both love Ursula Le Guin (when we met, we both had the same Le Guin on our nightstands), and he enjoyed Megan Whalen Turner's books very much (a good thing for our marriage). But there are rifts in the lute.
Leaving aside Red Shift, by Alan Garner (him-brilliant, me--runs sobbing from room to throw self off cliff), the foremost significant disagreement we have is regarding Mervyn Peake's Titus Groan series (him--brilliant, me--I cannot appreciate the brilliant writing because I am drowning in a wasteland devoid of any spark of human comfort). The secondmost significant disagreement is regarding Diana Wynne Jones--I have tried him on several, and he did not care for them and won't read any more.
So, being a social scientist, I would like to collect data with which to test my hypothesis that there is a negative correlation between liking Titus Groan and liking Diana Wynne Jones.