Hmmm... if I could transport myself back to, like, that era and mindset like magic? Probably Grand Theft Auto: San Andreas. GTA:SA was the first GTA I ever truly got in to. I owned GTAIII but never really played it. In college at the time, if I started playing the game someone would inevitably come by and want to play it instead... take turns, and they'd just go around blowing shit up or wreaking havoc. I skipped owning Vice City.
It wasn't until GTA:SA which I think I got at a discount going into the summer that I decided I was going to really sit down and play through the game... I played it that summer 2005, and got obsessed with it, absolutely loved it. I got so into the missions, side missions, story, everything about it. This was like pre-internet-ruins-everything, so there were so many urban legends and myths, I spent hours "looking for big foot" just like everyone else. I really loved the game. It was also a time in my life where things were pretty easy... I had just turned 21, I had a stupid cake summer job during college where I didn't do anything, I had a job lined up after the summer so this was basically just a time to relax, drink beer, play videogames. I had a girlfriend but she lived an hour away so we were only together sometimes, so I could really focus on the game. It was a good time.
That got me obsessed with all of the GTAs. I went back and replayed GTA:SA an VC on PC whenever those came out, and for a while I'd play GTA:SA every summer for a few years after that.
Resident Evil 4 was another fun one to play through. a buddy of mine and I beat it over a spring break, drinking beers each night and motoring through the levels. We didn't know what to expect with it, I hadn't played a Resident Evil game since RE1 on PSX, and so this was maybe... close 6 or 7 years later, maybe longer, and so I didn't have any expectations for how bat shit bonkers that story was and the crazy narrative turns, so we loved playing it. I remember my folks were away on vacation that week and I was house sitting, and my friend and I just marched through the game over a week drinking beer. Was a lot of fun.