I hate:
* hobbits and all stripes of halfling, though I hate the non-hobbity ones somewhat less
* drow, regardless of their alignment
* non-spellcaster-spellcasters (if magic is so hard to learn that wizards can't use a sword, how the heck does everyone else have time to just pick it up as they go?)
* vancean (vancian? vanceian?) magic
* 99% of d&d-related fiction
* nearly all the campaign settings but especially Greyhawk and Dragonlance
* the combat system
* how d&d societies are usually described more like Reneissance or Victorian age culture but we don't get steam power or gunpowder
* gnomes, gnolls, kobolds, orcs, trolls, owlbears, and most of the humanoid monsters as presented
* furries and anything that can be refered to as anthropomorphic and wasn't made by some sort of wizard
* how elfs, gnomes, sprites, and the rest of the fey are just humans with slightly different personalities
* the RPGA
* the lack of anything really fantastic in the fantasy. Everything, or nearly so, is acheivable or defeatable by the PCs, leaving nothing to awe or humble them.
I love:
* dropping un-statted creatures into adventures and letting them do whatever seems appropriately challenging at the time
* mixing Lovecraft and Steam-/Victorian-punk with standard fantasy
* weird environments
* coming up with reams of house rules which will never see play because I realize nobody wants to be bothered learning them
Oh, and I hate Tolkien's writing and studiously avoid gaming with total strangers (cons and the like included).