Okay let's play a game. The theist can only reply to the atheist (agnostic) and the atheist can only reply to the theist. The catch.... You can only say something good about the other belief. I'll start... "The agnostic are open to new ideas."
Oh my goodness, that could never be true. Atheists are far too smart for a mere Theists to create. They look and know all there is to know when they find neither hint nor scent of any evidence. They readily surpass even the renown thinkers like Albert Einstein and Kurt Goedel who thought they see the workings of a creator everywhere they probed. I guess they are closer to us mere mortal than the superior Atheists. No mere mortals could ever fabricate the perfection of the confident Atheists.
There are a lot of people without much hope. Politicians ignore them, they are poor, uneducated, they may suffer from illness. For the truly desperate with no hope of justice or progress, the mistaken belief that the villains in their lives will be judged and that they will have a better life after death is all that keeps them going. No matter how much you get shit on, somebody with power, the Creator, loves and cares about you, and he's got your back. That's extremely comforting. I think evolution selected for religious thinking for this very reason, as it's a great way to keep an organism going and reproducing when nothing else will. I'm obviously not religious, but I think a lot of atheists do religion a disservice when they ignore this. I don't think religion does more harm than good for this reason. I also think the main reason a lot of first world countries are becoming less religious is that their social safety nets prevent this kind of abject desperation. Without the desperation, the survival instinct of religion doesn't kick in as strongly. Good on you, religion.
if you mean open to belief in new ideas, then this is false by definition. agnosticism is the position that justified belief (knowledge) is not possible. in terms of assessing truth an agnostic considers "ideas" meaningless. if you mean open to being convinced by evidence, then that also applies to most atheists and, although to a much lower percentage, to some theists.
Einstein was a self-described agnostic and (at best) part time Pantheist, and was an outspoken ANTI-theist, so at least as far as he is concerned the implication of your statement is disingenuous.
You aren't playing by the rules. You are supposed to say something good about the other belief. Be creative!