I didn't expect upgraded consoles (PS4 Pro and Scorpio), and I didn't expect so many re-releases (i.e. remasters).

I didn't expect still not to have played the remake while I loved the original. (Technically I did play it a little, defeated the final boss for my wife)

I didn't expect pro and scorpio either, pro certainly not less than a month after PSVR launch.

I didn't expect the 4K battle to take all attention away from VR launching in less than 2 weeks.

I didn't expect ps4 slim, after neo announcement I expected that to replace the slim as ps4 couldn't be shrunk down.

I didn't expect xbox slim to have an internal psu nor psvr to have an external one.

I didn't expect Insomniac games to make an exclusive game for XBox One.

I didn't expect spending more time on Netflix this year than playing games.

I didn't expect getting bored with TW3 and Uncharted 4 before the end.

I didn't expect seriously considering a kickstarter indie retro puzzle 2D platformer for my goty.

Didn't expected that we will have DRM free gaming after initial Xbox One reveal. Was never interested in Nintendo systems. So I am glad it's not in this gen (next gen it's kinda confirmed).

Bolded; this was actually rather obvious from where I was sitting since consoles have added more and more features and will inevitably be likened to the market driving forces of our time, which are smart devices. The more feautures and breadth, the bigger the need for updates to keep up with the demands and wishes of the average potential consumer/customer for your product, I have always maintained that this will be among the hallmarks of the 8th gen due to the way the market has changed in the past decade or so. This was among one of many things I mentioned in the UNITY thread a couple of years back, along with MS being forced to drop mandatory Kinect and the Wii U's failure to gain traction in spite of software releases and advertising.

I didn't expect Nintendo to make Splatoon and it become a massive hit

I didn't expect Nintendo to make games for smartphones.

I didn't expect Pokemon Go to explode like it did.

I didn't expect Nintendo to make a runner game for smartphones.

I didn't expect Fire Emblem to make a smashing return.

I didn't expect Nintendo to fund Bayonetta 2, or make a Zelda dynasty game.

I didn't expect Sony and MS to make the Pro and Scorpio.

I didn't expect the Wii U to be such a sales failure.

I didn't expect the Wii U and PS Vita to sell as poorly as they did
I didn't expect MGS V to happen and then become open world and then get disappointed by it all
I didn't expect Konami to go off the rails
I didn't expect Shenmue 3 or The Last Guardian actually being a thing
I didn't expect the direction that Zelda is taking
I didn't expect the launch disaster for Street Fighter V
I didn't expect the slow start for Japanese games on the PS4, support for the PS3 lasted much longer than I thought
I didn't expect feeling that despite having new consoles for 3 years now, that the 8th generation has barely begun

Never expected a smash game to be better than Melee

I didn't expect so much personal turmoil, that my PS4 would sit dormant for 18 months. Then about a year later, have to move and put the fucker into storage again. Back to PS3 and Vita since July 11. Yay! Non-personal? Rocket League. The initial technical shock, and eventual acceptance of GTA 3 on PS4. How PS+ PS4 game, Styx: Master Of Shadows won me over after I was literally rolling mt eyes at it. How EDF became such a huge series for me. Aaaaand....What a massive, massive, MASSIVE step backward the PS4 is as a media player compared to the PS3. It inspired me to buy a backup, backup PS3. I may get one more.

Didn't expect any mid gen console at all.
Didn't expect ps4 pro to not have 4k blu ray drive.
Didn't expect current gen hardware to not die often. At this point in time I had 2 ps3 and 2 xb360 whereas I still have my OG ps4 from launch.
Didn't expect Destiny to not meet expectations.