Rather than just one indecent leading to a resignation, sometimes it's pattern of harassment, mistreatment, or other issues. Use this letter template when many issues have led to the decision to resign.
Dear Mr./Ms. Bossname,
I am resigning, effective immediately.
You should know that it's not just one incident that led to my decision; it's an entire pattern. I have never before witnessed such a toxic work environment.
I will be consulting with the appropriate oversight agencies regarding what I consider to be constructive termination. It is impossible for me to work under these hostile conditions.