> you find a good candidate, give them what seems like a competitive offer, then they disappear, and you learn after a couple of months they preferred my position, but got better pay elsewhere, where the difference is definitely small enough that we would cover it. If only the candidate wasn't so polite!

or maybe: "If only you didn't try to shortchange the candidate!"?

numbers on offer are the honest signal free agents get in the job market. if the jobs are similar enough, why should the candidate expend extra energy to achieve what is the default state elsewhere? why should they risk receiving a could shoulder because they negotiated "too hard"?