From the venerable and incomprehensible (oh, wait, I think I meant incontrovertible... no, that's not right... incompatible? interminable? oh, drat, it'll come to me... indefatiguable... um... indescribable... interesting... oh, to hell with it) Miss Snark:
I haven't actually asked the three agents who've passed on Jumping The Stream why they said "no", but I admit it gets under your skin the first time through the system. With hundreds of agents to go (and two still in consideration at the moment), I am quite confident I'll find someone to say "yes". Especially given the positive feedback I've received so far.