Xenoblade Chronicles-Before this game, my RPG experience was VERY limited (Paper Mario, Pokemon), and my true JRPG experience was pretty much non-existent. I knew the game had hype and had heard of Operation Rainfall, and I saw trailers of the characters running....and running...and running some more. Anyway, I had a couple friends who were pumped about getting it, so I jumped on the bandwagon (needing something to play after Skyward Sword). I was blown away. Actually, I was pretty overwhelmed by it at first. The scale and size. I played it a couple hours every week or so. I wasn't in love with it but the music was great, the world was huge, beautiful, and fun to explore and the story had me wanting to see what would happen. Things continued like that for a few months. Then, around 40 hours into the game, everything just clicked. I found out I wasn't even halfway, and I immediately started playing it a lot more and with a lot more enthusiasm. Needless to say, after 120+ hours in my first play through, another 25 in a NG+, and now another 70+ hours and counting in an ongoing second full play through, the game exceeded any and all expectations. It's a masterpiece and I can comfortably say that it is my favorite game of all time. Xenoblade Chronicles X can't get here soon enough!

The Last Story-Bought it because Xenoblade Chronicles opened my eyes to JRPGs in a big way. I didn't expect much from it based on the little I'd seen, but I ended up thoroughly enjoying it all the way through. I wish Mistwalker would bring a sequel or spiritual successor to Wii U.

Fire Emblem: Awakening-Wasn't on my radar at all when it was first announced. Played the demo though and was blown away. I immediately pre-ordered and the rest is history. 125+ hours between 2 play-throughs. The game is now my 3rd favorite game of all time.

God Of War: Ghost Of Sparta - I bought it soon after buying a PSP as I had to get an action game on it. I wasn't expecting much, but this game really amazed me with its epic scale, fluid combat and deep narrative.I like it more than most PS3 games and any PS4 game, in fact its my 3rd favourite game.

Couldn't think of anything at first, then I started scrolling through the comments and saw several people saying Xenoblade. Had a "*facepalm* duh" moment.

I hardly knew anything about the game before playing it. I was following Operation Rainfall stuff, knew a little bit about each of the three games, thought they all sounded cool. Even then when I knew Xenoblade was considered the 'best' (or at least the most adamantly requested), I didn't read much more about it than the other two. I signed the petition, promising myself I'd buy all three games if they were ever localized. That in itself is unusual for me, I rarely buy games without doing a great deal of research on them beforehand, especially at full price. But all three were localized, and I bought them all. Xenoblade is probably the best chance I ever took on a game I knew so little about.

Another game that comes to mind is Mario Sunshine. I didn't play this one until some time in the past couple of years. I expected it to be really good but not too hot. First few Shines disappointed even those relatively low expectations. But I kept playing and the game kept getting better and better; by the time I finished I ranked it just a hair below Galaxy and 64. It's an absolutely great game with maybe a dozen or so Shines that just felt stupid. Also, the controls in Sunshine are the best-feeling controls in the series.

Oh shit, Dark Souls. I don't know what else to say about that, I didn't think I'd like Dark Souls and then I played it, and then I played it some more, and then I played it a lot more, and now hot damn I love this game.

inFamous might count? I guess I wasn't really surprised it was good, maybe I was just surprised that it appealed to me once I got into it. It was kind of a slow process though, the first inFamous didn't blow me away but I liked it. I also knew inFamous 2 was supposedly better, so when I started that one and it was indeed better I wasn't exactly surprised.

The first time I can remember going from "what even is this" straight to "holy shit this is the best" is Smash Bros Melee. My cousin gave it to me for Christmas '01. I'd never heard of Smash before, didn't know most of the characters in the game. For some reason I mained Samus for a long time even though I knew nothing of her or the Metroid series.

Wonderful 101 (WiiU)
Max Payne 3 (Xbox360)
Animal Crossing New Leaf (3ds)
Trauma Team (Wii)
Pikmin 3 (WiiU)
Shin Megami Tensei IV (3ds)

Dragon Quest V, now I know why Japan love the series more than Final Fantasy.

Wonderful 101
boom blox
Xenoblade
The Conduit
Rage
All these games I had lukewarm expectations on, but all delivered an experience much better than I anticipated. W101 prob being in my all time top 20.

Plants vs Zombies: Garden Warfare. I bought it for curiosity but now I have played close to 200 hours

Also Bravely Default was far more polished than I expected. However Anges was so annoying it almost ruined the game.

Heavenly Sword - bought beacuse it was £4 in a bargain bin about 2 years ago, had a fantastic time playing it and ended up doing loads of research about the game and devs so I could follow them further.  Really good.

Hyperdimension Neptunia Re;birth 1 - series gets constantly slated, and yet this was an incredibly solid JRPG that I could recommend to pretty much anyone.

Pikmin - was given to me for free with a used Gamecube I bought in 2007 for about £30.  Ended up being mind-blowingly good.

Portal - I don't think anyone who played this at the time expected it to be as good as it was.

Summoner 2 - never played the first game; bought the second on offer and it ended up being one of my favourite games of the PS2 era.  Incredibly solid western action-RPG with lots of Japanese flavour in there.

Wild ARMs 3 - the other half of the offer in which I also got Summoner 2.  My first game in a series that eventually became one of my favourite gaming series of all time.  Fantastically well-made JRPG with an epic, sweeping story and beautifull unique world.

From the top of my head, there's three I can think of.

God of War 3: Got it from the bargain bin, so I thought I'd give it a chance. I expected it to be fairly cheesy and over the top, but while the latter is still true, it was over the top in a cool way and the game had better than expected mechanics and story. Got Ascension afterwards, but that was a total disappointment and completely failed to hit the mark.

Fire Emblem: The Sacred Stones: Besides knowing it existed I didn't know anything about the franchise until this game came to 3DS as one of the Ambassador games. I was completely blown away, it's brilliant in a lot of ways. So good even, that it earned it's spot in my Top 50 Best Games list.

Metroid Fusion: Entirely similar to Fire Emblem, I never played the game until it came to 3DS. Contrary to Fire Emblem though, I knew 'Metroid' was good. I never bothered with the game though because I thought the GameBoy Advance and it's games were mediocre. Looking back I have to admit that I missed at least two classics.