The speed of light often seems so fast as to be infinite, or at least hard to comprehend, in daily life. I was surprised the first time I calculated the minimum possible round trip time from New York to San Francisco, as the crow flies: it's just under 28ms not counting any overhead whatsoever from switching, electronics, etc. It amazes me that an actual network ping is only about double that, considering all the overhead of switching, and that light doesn't travel at full speed in fiber optic cables.
I worked on an algorithmic trade platform for an options broker/market maker. We bought rack space next to the ISE exchange's racks, which comes at a premium over rack space ACROSS THE ROOM.
It's a problem in mobile comms too. There's a concept called timing advance: in order for TDMA frames to arrive in the correct time slot and not crap all over the neighbouring frames from other users, they have to be sent earlier by the handset, depending on the distance from the base station.
(At least it's not GPS where the orbit speed plus lack of gravity means you have to factor relativity into the mix too!)
