I once worked on a project for a giant multinational, took 2 years, and was a complete catastrophe costing the company ~10M with zero value delivered. I'm sharing it because I learned a lot from it.
It was an internal project, so not even a real customer, other than the massively overfunded HR department.
We were to deliver a massive scope, an entire ecosystem of software/services to provide value for the 100K+ employees.
There was zero actual demand for it. Data clearly showed that the 100K+ employees of this massive company only needed two things: leave management and payslips.
And we were to add some 40 services to that, from a vast ecosystem of external vendors, homegrown crap, and integrating it all together. Every single piece of this new suite was specced up as if we needed NASA-level reliability.
I was puzzled from the start as to why we're even doing this, but soon realized I was overthinking it. It's busy work. It's one of the twisted incentives in corporations: be frugal and efficient to get punished, spend like a maniac and get rewarded. This is how kingdoms get created and inflate.
HR did not like to work with the internal IT department. Because they have an engineering mindset based on structure, whilst HR favors managing things Game of Thrones style. So to balance things out, not one but two external IT agencies were added to the mix, as "neutral" party between the internal departments. Mistrust from the get-go.
We're talking an army of consultants costing 200$/hr, producing documents and agreements that are treated as nothing but opinion. Some two months into the project, they understood the grim outlook of this project and got into the mindset that every hour of busywork is still revenue.
The customer, HR, acted like children, and that would be an insult to children. They would literally dream up the most outrageous requirements on the spot, just something they would personally like the system to have. Things that cost 100K to build and would save one person 5 minutes of work per week.
Any critical, rational feedback was fully dismissed, even if delivered diplomatically. Do it too often and they'd form coalitions behind your back to sabotage any of your next moves. This was of course a political setup in the making to ultimately blame IT for "failing to deliver".
As nothing actually got delivered for months, the inevitable came to be: let's launch a committee. I was on it. We spent our time producing meeting minutes of no consequence. Much needed hard decisions were unattainable as they required complicated coalition building that usually failed. Every head of every kingdom discussed things one-on-one, as if we're dealing with the mob. After a while, we used the committee basically as extended lunch, chit-chatting.
It took 8 months to deliver a first demo. A demo to ourselves, mind you. No actual user was involved. A few dozen people filled the room to see a tiny bit of poorly implemented functionality that nobody asked for. The mass psychology of it continues to fascinate me. An entire room full of people all knowing this is a sad joke, but nobody speaks up. There's even a forced hint of positivity: great progress, guys.
All of this kept going for nearly two years, after which the project was dissolved. About 25% of the scope was delivered. Our new solution for leave management and pay slips was worse than the old one, and everything else nobody uses. The 75% not delivered at all was fine as nobody wanted it anyway.
Nobody got fired and nobody had to justify the massive spend or any outcomes. In fact, the spend guarantees that a similar budget is to be granted to HR next year. Not spending this much would be very career limiting indeed.