Really cool thread KG, lets see
My first machine was a rubber keyed Spectrum 48k and the first ever game that made me feel that being at school was getting in the way of my gaming was World Cup Football (1984 Artic Computing Ltd) its just stick men kicking a square around but I loved it. I used to run like hell to get home to play it after school.
Then I got the c64 and it was Barry McGuigans Boxing that had me running home, although the music from Parallax had more of an emotional impact on me.
Onto Amiga and there must be dozens of games that had real impacts on me the Biggest was possible Midwinter I first played the game in the winter in the north of England and coming from a poor family (awwwwww) the heating for the upstairs and therefore my bedroom was never on (the condensation on the windows used to turn to ice over night). It really helped with the atmosphere of the game though and it was so immersive and well written.
A few others from PS and PC are Grand Turismo, I had dreamed of having a racing game like this, never touched the Arcade part of the game, just the Sim part and played it all the time before moving onto Grad Turismo II. On PC Fallout is one of my faves of all time, I'm such a fan of the series that I even like Fallout:Tactics.