This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / A Mind Forever Voyaging
One a lot of players may miss: if you go to the bookstore and buy a book in an early simulation, it turns into a treasured heirloom ... only to be destroyed by a cop in the later dystopia purely For the Evulz.
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.