FIRST OF ALL: the question is:
What style of prog do you like least?
not What style of prog do you hate?
well, i don't think any member here completely hates a subgenre: in this case, he has to explore more the subgenre: at least one hidden album is waiting for him!
there is obviously one subgenre that we least like than the others; to me, it is clear: KRAUTROCK.
however, i like amon duul & guru guru.
neo prog takes no effort to be appreciated: the effect occurs instantly!
keep in mind that when you do not like neo prog, you question the pertinence of modern keyboards, of expressive electric guitar solos and of atmospheric arrangements.
if you don't like neo, then you probably miss many musical styles, such like new age, metal, hard rock, electronic music, and most of the music that relies on modern keyboards