As I was still reacting to the news about the contract, the IRS seized my assets based on a clerical error on their part, resulting in an already tight financial situation turn into a nightmare. After being unable to find paying work for months, my vehicle was repossessed and I was evicted, broke with no support network.
Over the years since then, I've hustled to get back on track, but that one year's repercussions are still being felt today.
There is a deep, objective sense in which spending more than a year on a site that never got launched was bad. A permanent loss of meaning for that time. But it doesn't hit quite so hard as, for instance, being woken up every night for two weeks due to a bug I wasn't allowed to fix in an integration with our monitoring system, or when the amped-on-amphetimines founder threw a chair at the guy I was sharing an office with (and later explained how this was a better way to handle their disagreement than firing him, because he was really quite talented, wouldn't firing him have been bad for the company?) -- this made it impossible to work, the anxiety was just....
I think that's the odd part. A lot of the answers here have the distance of time, and know what's important. At the time, stuff like that, like having the management team demean and laugh at you for being concerned about honesty with business partners -- it has such a salient emotional impact it's hard to remember it's not even in the right category for 'worst thing'.
What's yours?
The first time was a very uncomfortable five days where they tried to convince me to say where I was going. I was heading to a competitor and they figured that much. I finally had a heart to heart with my manager and explained that if they trusted my integrity then they would know that I was not going to take any "trade secrets" with me. They backed off at that point and the rest of my stay was more pleasant.
The second time was at the next job. They asked me to stay and I said no. Then they said, "what if your offer were to disappear?", implying that they were going to somehow going to make enough trouble to have my offer withdrawn. I made it very clear I wouldn't respond to their threats and they denied making threats and didn't make them again.