I hesitate to relate the specific details of the actual stories I was told by people who worked with him, but they are consistent with the quote and the stories in the comments on this ATL post announcing his lateral move. (LinkRemoved)Anonymous User wrote:
What are these stories? I'm curious because I know someone who's thinking about applying to GT for M&A next year...
This article refers to him as notoriously belligerent.
I can say that one person who summered at a firm with DB told me that he saw him in the hall once and said, "Hi, Mr. Block, I'm Joe Black, a summer associate here at the firm." Dennis replied, "then why the fuck are you talking to me?"