I wrote it and rewrote it. I put xxxxxxx through some of it. Then I pulled it out of the typewriter (yeah, yeah, I know) and tore it up into tiny little bits and threw it in the bin.
As time progressed - and so did technology - there were many more of those letters. They turned into emails. They sat in my draft emails folder, with no email address.
They are the ''FOAD'' letters.
Or, to be as explicit as I can be at this hour of the morning, the Eff Off And Die note to a boss. It's the one you write when you can no longer bear the organisation; the pay rate; your line manager; and what it is you do, day to day, to pay your way. It's what you want to say when you resign.
Now, you can only write that note, filled with your honest-to-god responses, if you are absolutely sure that you never want to work at that organisation ever again. In it, you are detailing every mortal sin of your direct manager, her direct manager, the corporate culture.
You are now revealing what you really think, and from that you cannot resile. Once you've hit the send button, you are sent.
There are some beauties I've never sent.
The one where I said that I could no longer work in an organisation where one of the managers pressed his groin into the buttocks of the young woman who did admin. I realised that all I had to do there was tell a senior woman - I didn't actually have to resign myself.
The one where I wondered if I had to have my own penis to get a promotion.
The one where I wrote that I was moving to an organisation where the men and women had equal pay and equal working hours.
But no matter how well-written or witty those unsent emails might be, there can be no competing with Greg Smith, who sent his resignation letter (from investment bank Goldman Sachs) to The New York Times which printed it on its opinion page.
To be honest, when I first read the link I was sent, I was pretty sure Greg Smith was a pseudonym. Meh, I thought. No one in their right mind would say goodbye to such a powerful, high-status job in such a public way.
He tells us that he has worked at the company for 12 years, since he started as a summer intern. Then: ''I believe I have worked here long enough to understand the trajectory of its culture, its people and its identity. And I can honestly say that the environment now is as toxic and destructive as I have ever seen it.''
Smith was the kind of guy who was a real company man. He was so in the zone that he was used for the recruiting video; was part of the team that mentored and recruited new staff.
And he wrote last week: ''I knew it was time to leave when I realised I could no longer look students in the eye and tell them what a great place this was to work.''
It's gripping - although he nearly lost me when he started to complain about the company wanting to make big profits. Isn't that what capitalism is about?
But it was the bank's response, leaked to Bloomberg News a day later, which sealed the deal for me. It was so pathetic in its inability to deal with Smith's complaints of toxicity, greed and desperation that all it could do was to claim its last staff survey was positive and that 89 per cent of the 85 per cent who responded thought client service was exceptional.
My maths says one-quarter of staff said something different.
Plus, anyone ever done one of those surveys?
They usually go: ''How happy are you in your job, where five is ecstatically happy and zero is moderately happy?''
And don't forget to fill out the data which requires such a detailed response it puts an EPIRB - emergency position-indicating radio beacon - on your desk and then tracks you when you go to the toilet.
So then I waited for Goldman Sachs to pull out the big guns and say Smith was a loser who beat the company to the punch. Instead, all they could say was that he never complained when he had the chance.
I'm wondering how a complaint about corporate greed would go down in an investment bank.
That's where we all are, of course, even those of us who are ecstatically happy in our jobs. Line managers have no interest in fixing small things; and their supervisors are too busy managing upwards to try to fix bigger problems. I've only ever worked with one boss who would really deal with complaints and see them as an opportunity and not a catastrophe.
Which is why most of us write those emails but never send them.
In our hearts - and in our draft email folders - we are all Greg Smith. We just don't back ourselves to press send.