Micro-management and disrespect from supervisor. During an introductory call with a representative from the government, who was not at all happy with the company's compliance efforts prior to my arrival, my direct supervisor told this person when referring to me, that he would "drive him like a mule and make it a full-time job!" How disrespectful is that? I knew at that point that it wasn't a good fit and I resigned shortly after that.
I wrote an email to the company president to tell him why I had resigned after only a month, thinking I owed him an explanation, but I never received the courtesy of a reply.