Pretty-much any time they let Tasha Yar speechify.  The "just say no" screed she delivers to Wesley, the "get down on your knees" speech about the Feddies in the pilot.  I don't know if Crosby deciding to leave TNG in the first season was a good carrer move for her, but it was a good thing for the show she was gone.  IMO.  YMMV.
	
		
			
		
		
	
				
			
				

 

