Well... how to make this visible? If you imagine a tube that is just wide enough to contain a single marble and you fill that tube with marbles all the way then you can also image that if you push one new marble in on one end instantaneously another one will pop out the far end. It's almost as if the marble you put in came out the other end. So even though the electron (the marble) moved very slowly the signal propagated extremely fast.

Wireless hardware shares a chunk of the spectrum, much like cell phones share a chunk of the spectrum. So a node is not always transmitting the way a full-duplex ethernet connection is. Your packets wait for their slot to open up and then they are transmitted. The same happens on the way back. So the throughput can be extremely high but the latency can be murderous at the same time. And that's assuming the packet made it in one piece and did not have to be re-transmitted, in which case the lag will be even longer.

I hope that explains it clearly enough.