Continuity mistake: When Mindy arrives at work, she goes into Danny's office and finds him on the floor in his underwear. She closes the door behind her, but a few seconds later, the door is wide open again. (00:02:25)
Dinner at the Castellanos - S3-E15
Continuity mistake: While Mindy is eating dinner and talking to Dani about getting off gym class, after she mentions the pentagram she puts her knife down and switches her fork to her right hand. The angle changes, and she's holding both items of cutlery in the correct hands again.
Continuity mistake: Casey says that Mindy didn't return the engagement ring, but at the end of the episode "The Other Dr. L" she gives him the ring, he walks out of her apartment and then she cries while National's "Need My Girl" plays in the background. (00:20:20)