A Mind Forever Voyaging/Tear Jerker


 * The ending.
 * What really felt like a punch to the gut was playing 2071 and 2081 in one sitting for the first time. And, like Planetfall, this was all text.
 * The short story prologue. Most of the Perry Sim sections are Tear Jerker material, and knowing that they're all part of his successful growing process towards true AI just makes it worse.