Revealing mistake: When Rita confronts Dexter about his accident being more than minor Rita turns the buggy with the baby in around to leave and it is clear the baby is fake. (00:38:20)
Dexter (2006)
1 revealing mistake in Remains to Be Seen - chronological order
Starring: James Remar, Michael C. Hall, Jennifer Carpenter, David Zayas
Dirty Harry - S4-E5
Continuity mistake: When Dexter listens to Officer Lundy's tape recording, we hear Lundy say that the Trinity killer's weight is 190 to 200 pounds. When we saw him recording that, he said 200 to 220 pounds.
[MC Hammer's "U Can't Touch This" playing.]
Former Classmate: Come on, Dexter. It's hammer time.
Dexter: [internally] I have no idea what hammer time is. Or how it differs from regular time.
More trivia for Dexter
More questions & answers from Dexter
Answer: Two reasons. First, as a cop he knows that there are lots of murderers walking around free due to flaws in the system so he uses Dexter's "urges" to right the wrongs in the system by taking out people who have no right to walk around free. Secondly, by taking him to a psychologist he runs the risk of having him committed and he doesn't want that for obvious reasons, so he figures it is best to channel his urges to what he considers a greater good.
The_Iceman
In addition to the earlier answer, in the last season (8th) of the show, we are introduced to Dr. Vogel, whom Harry had been discussing the situation with Dexter as well, and it is shown on-camera that Harry describes what Dexter has done (killing)... So, technically he did consult a psychologist/psychiatrist, just not having Dexter and her actually meet. But Dr. Vogel was aware of whom it was and how to intercede.