Resignation is like dying. The organizational announcement of your leaving the fold is like your eulogy. Naturally, there will be nothing but good praises in both a eulogy and organizational memo but unlike the latter an organizational memo about a departing member is done only for those in the higher ladder of the company and may not always be accurate.
I'm sure that you have encountered top management bosses who did not go up the corporate ladder through merit. It's sad when this happens because it would mean a waste of company resources. Call it a perk of the position that you get a flowery send off even if you did not contribute anything to the company. Some people are really lucky (if you can call it that).
When we die and finally meet our Maker the only question He will ask is, "What good did you do when you were still alive?" My advice: Don't ever be left without an answer. Well, you know where you'll go if you don't have anything to say, right?
In the corporate world, leaving a legacy of industry and productiveness is the best way to say good-bye. You are genuinely remembered for your contributions and as a person to epitomize. And even without the benefit of a corporate memo, your departure is felt with a genuine void.
For those whose tenure is without meaning, no amount of ornate literary composition can hide your true value---NONE. And to whatever corporate memo there is about your departure people will only say, "So...?"