Why I left - a pre mortem exercise

In "pre mortem" exercises, we imagine a future failure that has happened. They help us identify risks and blind spots to avoid that failure.
Take 30 minutes of your time for the following exercise.

Why I left

Fast-forward one year into the future.
You're done with Syslifters.
You write your resignation letter.

Explain in detail what drove you to leave.

The letter is personal. Nobody has to read it.

We would appreciate if you presented our group the key reasons why your future you left us and how we can improve our company, our collaboration, your satisfaction.