Easily Raef LaFrentz.
He represented a total downfall for the Celtics and ridding the team of by far my favorite player (possibly of all time) in Antoine Walker. Anyone with any sense had to know that a big, slow dope like LaFrentz wasn't going to be good and his contract was atrocious (like 5 years 65 mill).
I understand people wanted Walker out of town, and while I totally disagreed with that concept, I more disagreed with the player we got in return. When I had heard we traded Antoine to Dallas, I was like, "well, at least we are getting Jamison in return", but when I found out it was Raef, I nearly dropped dead.
This was really the beginning of many many many bad moves made by Danny- yes, draft included (Al Jeff and Rondo fell into his lap, no one else has been THAT impressive). He was able to save himself with the magic of it all in the Summer of 07, but don't tell me that Raef was all part of the plan (and Jiri Welsch was not enough additional compensation). We could have gone for Ratliff much earlier or even better, traded for an expiring contract.
All these memories coming back to life- really angers me...heck, at least we are good now...