I can't stand:
a) avant-gardism done just for the sake of being "original" (aka uninteligible).
b) over-pretentious jazz-pop.
c) the worthless Puerto Rican-Dominican deformation of hip-hop.
EDIT: d) anything 'sung' by Shakira, Ricky Martin, Enrique Iglesias, Janet Jackson, Justin Bieber or others of their kind.
All of the above are surefire ways for me to detonate a headache or nausea.