A (slightly indirect) co-worker is retiring tomorrow, and so he has been steadily decommissioning his sysadmin's collection of machines over the past while, sending my group a stream of 'please remove this from DNS & DHCP & etc, it's gone' update requests. Seeing these go by is giving me feelings, especially with the final few today (his most central machines).
Maybe it's a bit like the famous scene from 2001 of HAL having its circuit boards pulled.