For me, it was the game Rocket Jockey released by Sega Soft in '96. It was perfect. The game featured a surf rock soundtrack by Dick Dale. The entire premise of the game was to ride around on rockets and using long cables to yank your opponents off theirs. Referees were also fair play. I don’t think I’ve met anyone else who has played the game, so if you have, let me know!
SimAnt holds deep reverence with me since I remember playing it at my friends house all the time as a kid.
Lands of Lore, Ultima Underworld, Wing Commander, and Master of Orion, because I played them with my brother all of the time.
And Police Quest and Number/Word Munchers because they were some of the first I played in school.
Oh and King’s Quest V (and really all the Sierra games, for that matter) have honourable mention because I played it ALL THE TIME at my dad’s and I miss those days.