wow.. i wouldnt think i would be the minority on this, but it seems i am.. I don't care much for same day call backs. If i give out my number or get a number, I don't think I ever call back that same day unless there are special circumstances (night cut short by some problem, etc).
it isn't playing a waiting game so much as allow me time to think about what happened. however, i do agree waiting so you don't seem desperate is a bit silly
either you are, or you aren't. When you call has no bearing on that.