The thing that irritates me the most is how regions work on Steam, namely:

1. I can't buy a different region game to gift. Since I'm living in CIS, I can only buy games for friends in the CIS region.
2. Different prices for different countries in the same region. Why do I have to pay 40% more than Russians if we're still getting a CIS region game?

2 things:
-Not being the only platform
-GabeN :|

The prices, it's too expensive.

• My problem with the Steam is their automated cold-hearted support that don't manage to help us with simple stuffs... I can't complain much about that but i had some problems with the support and i know it's for my account protection, but it's annoying to receive only pre-molded answers and a "we can't do nothing about it...".
  I've waited a month to use marked again because i changed the mobile auth for e-mail, then email didn't worked so i went back, then over this period i've changed my smartphone and had to wait more... So, 15 + 7 + 15 days awaiting for sell my cards again hehehe. (Done +500 cards)

• The Steam client is cool but it could separate the categories automatically, but i can resolve it with Depressurize that is awesome too, but would be nice and more organized if the client were responsible for that.

• My profile pic is ugly, but i must blame my parents for that.

Greenlight. Good thing they're killing it off. Pulling the plug. Pushing a pillow over its $(!@stain covered face.

The fact there's no "invisible" mode. like sometimes I don't want to socialize or some people bother me...
but guess will stick to "Away" for now.

Before Enhanced Steam, I hated how bad the videos on the store page were. Always went to youtube to see what the gameplay actually looked like and not some terribly edited advertisement. Bad screenshots too, don't know how they do it but they do.
But that was before Enhanced Steam. Now it's general stuff about the store like not having enough filter/sorting options and unhelpful reviews.

Not being able to rename entries. Some series' naming conventions suck, or are inconsistent
It's a mess

other:

the fact that
DDX27-ZJVGA-0HAVY
there's so much
428IX-9KZYX-FHHLV
garbage that
AWHPX-ZDHH4-80T5Y
gets greenlighted
3EAA6-6C8E5-KRDFZ
for some reason

Every profile has blue showcases and a blue summary box. You can change the color with Enhanced Steam but only other Enhanced Steam users can see it. I just wish that if I had a red background, i could change to a red theme, and so on.

I can't sort my groups in any way
I can subscribe for comments on a person's profile, but I can't subscribe for group announcements (WTF)
The let me use any collected badge level would be a nice addition as well, but the lack of that aren't impairing the site's functionality at least.

Region locked games and regional stores that have very cheap games for some.

All Steam games should be ROW with one world wide price.

heart-emoji-"art" 😤
😎

Region locks and their shitty client.

Videos are a non-issue since they are sold in my region for the most part :D.

Removed games ... it is part science and part art at the current rate. The amount of info that is filtered through to get even a slight heads up before something is nuked is amazing. Thank God most RGC peeps work together or it would be hell.

Valve's way to talk with community (through updates as they say), for example not fixing some issues with client, like this one:
http://steamcommunity.com/discussions/forum/1/490123938427369104/

The worst thing about steam is, for me, customer support and I've only had to deal with them a couple of times.

Two sides of the same coin:

Heads: The Steam Client. The non-browser version has always been awful, and the browser version is only "good" by comparison. For a company with as many silos full of cash as Valve has, it's a glaring way to say, "Please stay on the line, your money is very important to us. And that is the only thing."

Tails: Steam Tech Support. It is robotic, even when performed by a person, cares nothing for your troubles, and is as hyper-sensitive, volatile, and vindictive as a spurned lover.

Other than that, it's peachy.

The joke "reviews"

that i cant hide a game from my library (example: i have bioshock and when remastered came out i got it automatically and now i have 2 bioshocks in my lib and i cant remove one without removing other and i cant hide, and no, setting it to hidden category in steam is not hiding it because it is still visible on my games lists online), family sharing that cant share just one game instead of complete library

The overwhelming flood of fan service bullshit, greenlight exploits to make a quick buck on shitty software (can't even call it videogames), awful customer support, people treating it like social media and uh... oh, yeah! In-game items that spawned gambling and other practices that have nothing to do with gaming, but worst of all is that they have a monopoly and you have to deal with it. I mean, sure, you could use GOG, DRM-free, uPlay et cetera, but... Nah.

Others -
1) Gamers have levels for how much money they have and not for their achievs like in PS and Xbox;
2) Almost no quality control in what games enter on steam.

Indie games

the update crap. why cant i play a damn sp game i prepared for somewhere where i cant download only because it has an update waiting?
it makes sense for mp since everyone needs the same version, but nobody can tell me the sense for a sp game to make it not startable if a update is awaiting.