* Bigger beak = More powerful bites (Although the worst bites I've ever gotten are without a doubt from my Meyers

).
* Bigger beak = Greater rate of destruction on your belongings.
* More mess to clean up.
* More expensive toys (that are also ruined much faster).
* (Often) louder voices.
* More food, more expensive.
* Larger wingspan, the bird can't get enough exercise just flying around indoors = frustrated bird.
* Bigger bird = MUCH bigger cages, which are hard to find, very expensive and takes up a LOT of room.
* Bigger (and heavier) transport cage you have to carry around if you go somewhere. (To find a good macaw carrier is near nightmare.)
* Harder to find a bird sitter if you have to go somewhere and can't bring your bird...
* ...and bringing your bird IS harder the bigger it is.
* An aggressive bird is much more intimidating the bigger it is, and if you fear the bird, it can only be destructive to your relationship with the bird.
* Bigger claws - bigger scratch marks on your hands and arms. If I have my little Meyers on my hand or arm, I can barely feel it, or at most get a few thin scratches.
When I had my Eleonora Cockatoo (or now, my Macaw) on my arms... gawd. A short walk, and my arm is red and swollen from all the scratches. To have the Macaw with his gigantic claws on (or rather "in") my hands HURTS LIKE HELL. And no, they don't need clipping. Birds claws are supposed to be longer than those of dogs for example, since they need them for grabbing branches.