Pretty standard answer but Sonic 1 and Sonic 3 is the reason why I decided to sided with Sonic as a child until I realized is okay to just love any video game and console, at some point is just made me natural happy beat Sonic 3 constantly.
Contra Hard Corps is one of the reasons, Contra is top 3 franchises for me, the first time I played it I didn't knew games could be that good, honestly, still one of the best games I ever played.
From there, I guess there more games I like, personally I would recommend to watch some of the documentaries about how some classic games like Castle of Illusion starring Mickey Mouse or Street of Rage were made, they certainly include a lot of memorable stuff and will probably inspire you to want to create or something or at least respect the thought process that went when making these games and a lot more for the Sega Genesis/Mega Drive.
Anyway, there more games and development stories I particularly love, but it would be a post too long, you can tell a console is good when even 30 years later people still remember it and still sharing their favorite memories and stories about how the development of the games were for the console, one way or another is the perfect example of a legacy that is still respected up to.this day.