Plenty of decent teams have lost to the Clippers this season.
The Celtics had crappy games against mediocre teams all the time last year. At least in this game the Celtics didn't give up and actually tried at the end to make a game of it and come back. The '10 Celtics would not have made that much of an effort. So in that sense, this game was rather encouraging.
Every team has an off night fellas, don't make a big deal out of it.