First company:

- being sat at an office that didn't have chairs with proper back support. It would kill my back every day. Like sitting on a bar stool coding.
- not having access to basic resources (cafeteria, salary bonuses)
- being seriously underpaid ($200 under)
- not having an IT process pipeline (yeah, this is a huge one): no JIRA, no git, no VCS, no continuous integration, etc. I fucking spend 45% of the time fixing coding-unrelated shit.

Second company (very aggravating):

- dumb frontend bitch and privileged colleague who both kept telling me months on end to shut up and who wouldn't listen to my advice on anything, while my advice would actually help the company advance in productive ways. The key here is being told to shut up while stagnating. i.e. dead end job.
- people advancing in the company based on nepotism and favoritism, based on having tits and ass, rather than skills and independence.

- pointlessssssssss meetings where decisions are made solely based on the opinion of Mr. favorite senior dev. The rest just sits there like a bunch of sad saps and yay-nodders. Incompetent PO's who "would like to hear your input" but then when you give it, they completely dismiss you.

- pointlessssssssss monthly meetings with stakeholders, where the dev teams do nothing but clash and act like pussies in front of the PM just to get in his favor, but behind scenes continue to make the same mistakes and telling the CEO everything is fine. Goodness, how can it get more unproductive.

- completely antisocial and nepotistic 'colleagues' who won't even talk to you, let alone smile at you or be friendly. You saying good morning and them pretending you're vapor that doesn't exist. Go go company atmosphere! Especially during lunch, those are the worst times. Imagine sitting at lunch where everyone looks like you killed their dog and the rest is huddled up in little high school groups.
What else? The incessant and pointless smalltalk that makes me want to bang my head against the wall. Talking about dogs, kids, what show was on tv last night. The fuck man, do you have a brain?!

Third company:

- HR bitches who think they are the shit and developers are antisocial, helpless misfits, but they work with computers and they don't even fucking know what a status bar is! The irony!

- forced socializing and stigmatization for the opposite. Imagine coming into a company and you don't say good morning. Should that be a problem? No. Instead, everyone starts dogging on you and hating you just because you didn't smile in their faces and said: hiiiiiiiiiiii how did you sleep? Did you feed your dog? Fuck you.
Elliot (Mr. Robot): "Wouldn't it be awesome if there was a mute button for life?" -boop, boop, boop, boop...- Ahh.. there.. that's much better."

- CEO's sucking up to you but when it comes to salary increase, they say shit like: "Ahhh ya know, it's kinda difficult." Yet another dead end job.