Agreed with all above...

I've found that my truck takes a long time to reach operating temp by simply idling, so I don't let it idle for any length of time. If plugged in, I start it, put on the seat belt, adjust radio, etc, then go. If not plugged in, I wait until the idle settles to steady (~ a minute), set the throttle at about 1000rpm, then drive slowly/steadily for the first 5 minutes. As SOON as I start driving, the temp gauge starts rising, and it heats up very quickly.

For shut down, I do like the rest of the folks here: drive slower (keep the turbo boost to a minimum), for the last couple of minutes.

I think 5 minutes shutdown time is excessive, and a waste of fuel, if you're smart about cooling it down 'before' you stop driving...