We have talked about tech. in presentations and this is from:David Pogue, at the New York Times, talking about what he carries in his bag when he travels:
* My video dongle. Grrrr! I can't stand the way Apple
laptops require an external three-inch video-adapter cable
to connect a standard projector--and, worse, Apple changes
it with every new model!

Just ask the A/V guys who have to accommodate public
speakers around the country; every one of them can tell you
tales of keynote speakers who showed up without the dongle,
and couldn't show their slides. (The really good the A/V
guys actually own a complete set of Apple laptop dongles
just for this purpose.)

Anyway, I used to lose these overpriced adapters by leaving
them connected at the podium. Now I put my MacBook Air's
dongle right back into its bag compartment when I leave the
stage. Religiously.