Worst dev team failure I've experienced?

One of several.

Around 2012, a team of devs were tasked to convert a ASPX service to WCF that had one responsibility, returning product data (description, price, availability, etc...simple stuff)
No complex searching, just pass the ID, you get the response.

I was the original developer of the ASPX service, which API was an XML request and returned an XML response. The 'powers-that-be' decided anything XML was evil and had to be purged from the planet. If this thought bubble popped up over your head "Wait a sec...doesn't WCF transmit everything via SOAP, which is XML?", yes, but in their minds SOAP wasn't XML. That's not the worst WTF of this story.

The team, 3 developers, 2 DBAs, network administrators, several web developers, worked on the conversion for about 9 months using the Waterfall method (3~5 months was mostly in meetings and very basic prototyping) and using a test-first approach (their own flavor of TDD). The 'go live' day was to occur at 3:00AM and mandatory that nearly the entire department be on-sight (including the department VP) and available to help troubleshoot any system issues.

3:00AM - Teams start their deployments
3:05AM - Thousands and thousands of errors from all kinds of sources (web exceptions, database exceptions, server exceptions, etc), site goes down, teams roll everything back.

3:30AM - The primary developer remembered he made a last minute change to a stored procedure parameter that hadn't been pushed to production, which caused a side-affect across several layers of their stack.

4:00AM - The developer found his bug, but the manager decided it would be better if everyone went home and get a fresh look at the problem at 8:00AM (yes, he expected everyone to be back in the office at 8:00AM).

About a month later, the team scheduled another 3:00AM deployment (VP was present again), confident that introducing mocking into their testing pipeline would fix any database related errors.

3:00AM - Team starts their deployments.
3:30AM - No major errors, things seem to be going well. High fives, cheers..manager tells everyone to head home.
3:35AM - Site crashes, like white page, no response from the servers kind of crash. Resetting IIS on the servers works, but only for around 10 minutes or so.
4:00AM - Team rolls back, manager is clearly pissed at this point, "Nobody is going fucking home until we figure this out!!"
6:00AM - Diagnostics found the WCF client was causing the server to run out of resources, with a mix of clogging up server bandwidth, and a sprinkle of N+1 scaling problem. Manager lets everyone go home, but be back in the office at 8:00AM to develop a plan so this *never* happens again.

About 2 months later, a 'real' development+integration environment (previously, any+all integration tests were on the developer's machine) and the team scheduled a 6:00AM deployment, but at a much, much smaller scale with just the 3 development team members.

Why? Because the manager 'froze' changes to the ASPX service, the web team still needed various enhancements, so they bypassed the service (not using the ASPX service at all) and wrote their own SQL scripts that hit the database directly and utilized AppFabric/Velocity caching to allow the site to scale. There were only a couple client application using the ASPX service that needed to be converted, so deploying at 6:00AM gave everyone a couple of hours before users got into the office. Service deployed, worked like a champ.

A week later the VP schedules a celebration for the successful migration to WCF. Pizza, cake, the works. The 3 team members received awards (and a envelope, which probably equaled some $$$) and the entire team received a custom Benchmade pocket knife to remember this project's success. Myself and several others just stared at each other, not knowing what to say.

Later, my manager pulls several of us into a conference room
Me: "What the hell? This is one of the biggest failures I've been apart of. We got rewarded for thousands and thousands of dollars of wasted time."
<others expressed the same and expletive sediments>
Mgr: "I know..I know...but that's the story we have to stick with. If the company realizes what a fucking mess this is, we could all be fired."
Me: "What?!! All of us?!"
Mgr: "Well, shit rolls downhill. Dept-Mgr-John is ready to fire anyone he felt could make him look bad, which is why I pulled you guys in here. The other sheep out there will go along with anything he says and more than happy to throw you under the bus. Keep your head down until this blows over. Say nothing."

Like most people I needed some extra cash during uni, so I proceeded to learn CSS + Photoshop (yeah, I know). Followed by PHP and WordPress.

It can be a very shitty platform until you realize that you can stop combining plug-ins from all over the place with dubious code quality and roll your own.

Anyhow I kept at it until I was able to join a niche company doing a quite popular caching plug-in for WP (yeah, W3 Total) when I suddenly became *very* interested in anything and everything performance.

This landed me a very cozy consulting gig in the Nordics - they were using WP for an elephant-traffic website and had run into a myriad of perf issues.

Fixing them and breaking the monolith awarded me with skills in nodejs, linux, asynchronous caching among others.

I was soon in charge with managing the dev boxes for the entire team, and when the main operations dude left, I was promoted to owning the entire platform. (!) Tinkering with Linux for most of my life really came in handy here. (remember Debian potato?)

Used saltstack + aws cloudformation to achieve full parity between all environments. Learned myself some python and all various tips and tricks which in the end amounted to 90% reduction in time-to-first-byte and considerable cost savings.

By the end of the 2yr contract I had turned myself into a fullstack systems engineer and never looked back.

Lawyers not getting along resulted in us having to abandon NewRelic, so I got to learn and deploy the ELK stack as a homegrown replacement, which was super-fun.

Now I work in the engineering effectiveness department of a Swedish fintech unicorn where all languages under the Sun are an option (tho we prefer Python), so the tech stack is unlimited. Infinite tools and technologies, but with strong governing principles and with performance always in mind so as to pick the right tool for the job.

It's like that childhood feeling when you've just dumped a ton of Lego on the floor and are about to build something massive.

I guess the morale here is however disappointed you feel by your current stack - don't. Always strive to make things better, faster, more decoupled, easier to test, etc. and always challenge yourself to go outside the comfort zone.

Crypto. I've seen some horrible RC4 thrown around and heard of 3DES also being used, but luckily didn't lay my eyes upon it.
Now to my current crypto adventure.
Rule no.1: Never roll your own crypto.
They said.
So let's encrypt a file for upload. OK, there doesn't seem to be a clear standard, but ya'know combine asymmetric cipher to crypt the key with a symmetric. Should be easy. Take RSA and whatnot from some libraries. But let's obfuscate it a bit so nobody can reuse it. - Until today I thought the crypto was alright, but then there was something off. On two layers there were added hashes, timestamps or length fields, which enlarges the data to encrypt. Now it doesn't add up any more: Through padding and hash verification RSA from OpenSSL throws an error, because the data is too long (about 240 bytes possible, but 264 pumped in). Probably the lib used just didn't notify, silently truncating stuff or resorting to other means. Still investigation needed. - but apart from that: why the fuck add own hash verification, with weak non-cryptographic hashes(!) if the chosen RSA variant already has that with SHA-256. Why this sick generation of key material with some md5 artistic stunts - is there no cryptographically safe random source on Windows? Why directly pump some structs (with no padding and magic numbers) into the file? Just so it's a bit more fucked up?
Thanks, that worked.