I took a tour of an air traffic control facility, this afternoon, and learned a few things from a controller's perspective. We couldn't take photos as we toured the actual floor of the air traffic control center, but we were allowed to snap pictures in the training center; they look almost identical.
1. There are three basic types of air traffic controllers, each of which is highly specialized: those who work in the towers at the airport, those who work in the "centers" that handle en route traffic, and approach/departure terminal controllers who handle traffic arriving and leaving the airspace outside of an airport. So, a center controller hands traffic over to a terminal controller who would then hand traffic off to a tower controller for landing at an airport. Simple concept, tricky execution, especially when there's a VFR pilot flying close to controlled airspace (like Class B) and not talking to any controllers, which is perfectly legal when flying VFR (i.e. not on a flight plan).
2. Air traffic controllers jokingly refer to jumpers (parachutists) as "meat rockets." (Parachutists don't show up on radar.)
3. For IFR pilots: It's rare that a controller will ask a private pilot to fly an "unpublished hold," especially on a VOR. In other words, it would be rare for a controller to tell a pilot, "Hold east of the Oceanside VORTAC on the 090 radial, left turns, maintain 5,000', expect further clearance 0+50." The controllers probably wouldn't know the exact phraseology, either, and VORs are going away in lieu of GPS. For private pilots in small (slow) planes, controllers would rather simply give a pilot vectors to fly a box rather than a racetrack (see last photo).