[A wave of relief comes over him, awkward circumstances aside.]

I understand. But remembering pain is as important as remembering joy. [Even if he did seem to forget whatever happened immediately before he came here... something linked strongly with pain.] And... before I knew it, I had hair. Then we spent some time in the Fire Nation, getting ready for the invasion. [He looks down.] That's another bad memory. When I let everyone down, including including your father and all of you.