Mind-Breakers

Joker: Doing? You're doing what any sane man in your appalling circumstances would do. You're going mad.
Gordon: I... I remember-
Joker: I wouldn't do that. Remembering's dangerous. I find the past such a worrying, anxious place. Yes, memory is so treacherous. One moment you're lost in a carnival of delight, childhood aromas, the flashing neon of puberty, all that sentimental candyfloss. The next, it takes you somewhere you don't want to be. Somewhere dark and cold, filled with damp, ambiguous-shaped things you'd rather forget. Memories can be vile, repulsive little brutes. Like children, no?
Gordon: Barbara!
Joker: But can we live without them? Memories are what our reason is based on. If we deny them, we deny reason itself. Although, what's wrong with that, really? It's not like we're contractually tied down to rationality. There is no sanity clause. So when you find yourself locked onto an unpleasant train of thought, headed for places in your past where the screaming is unavoidable, remember this: there's always madness. You can just step outside, close the door on all those dreadful things that happened. You can lock them away... forever.