An engineer at Sun Microsystems' Fishworks lab discovered that yelling at your hard-drive causes sharp (yet momentary) increases in the hard-drive's latency. The engineer demonstrated this by yelling a portion of a server holding a RAID JBOD array, while monitoring its IO/s and latencies of the drive he was yelling at it. Each time he yelled at it, there was a surge in the drive's latency.
This opens up some interesting topics to research on, of how the rather loud environment enterprise hard-drives are put through in high-density storage environments impact on them, and to what extant vibration dampening helps them.