What “damage” specifically, has he done?
It's not just H2O - he's just incompetent AND talkative.
It's been my experience that most Republicans have a very hard time answering this question. I quizzed my Conservative family members on this over Christmas; none were able to articulate a real argument about things he has done that have damaged our nation. The best criticisms about him that they presented, were actually ones from the LEFT - that he hadn't done enough to turn the recession around.
They can't respond cogently, b/c their favorite arguments don't work. They can't blame him for raising taxes, as he actually lowered them. They can't blame him for the Auto Bailouts, as 1)they started under Bush in 2008 and 2) they actually worked out pretty well. Can't call him soft on foreign policy, he's managed to wind down Iraq, we won a war in Libya with no real losses, killed Bin Laden and decimated AQ. Can't really even blame him for Obamacare, b/c EVERY conservative I've ever spoken to WANTS almost every feature of the ACA to remain intact, other than the mandate. The sane ones realize that it's never going to be repealed.
What we end up seeing are second-tier complaints: he spends too much, too many new regulations, he's a 'socialist' - never mind the fact that he's never done a single socialist thing, ever - he apologizes for America, et cetera. Character attacks seem to rule the day, as their nebulous nature allows them to be essentially irrefutable by facts and logic.
Questions like yours to the waterboy are extremely frustrating to them, as they have a very difficult time expressing the large amount of antipathy they have in their hearts for the guy. I'm sure you can guess at some of the motivation behind the underlying emotion, though - one, a certain amount of latent racism and xenophobia; and two, an anger over the fact that he managed to outmaneuver the GOP time and time again over the last three years (though not as often as I would have liked).