I would say the scenes between Luke and Vader. When luke speaks of his former self Vader walks away but you dont see emotion on his mask. Its indirectly implied thru the music and his tone of voice. And the end when Luke begs for his life. He looks back and forth and the only thing you see is the lightning glow on his helmet and mask. Its almost as if he stares at what is happening and you know what he is thinking. He is torn between serving his master and saving the son he never had but always wanted. At which time he chooses his son. The only implied feeling of pain is the lightning on his body but you dont see his face. Its all implied yet we give Darth Vader all the facial expressions that Luke or anyone would have given. The youngling scene in ROTS was chilling but only implied with the lightsaber. The cockney youths line does make it tragic though. Any scenes implied but not seen do it for you.