The scene in Citizen Kane when his wife leaves him and her image is reflected in room after room of mirrors.

There is another scene in Citizen Kane where one of his elderly employees (name escapes me) is being interviewed. He muses about seeing a beautiful girl on a ferry and falling in love with her although they never met. The image drove me crazy for years because I couldn't remember where it came from. Still plays in my mind at odd times. The opportunity lost?

Horror movies? The Haunting. Julie Christie is in bed in a dark room holding her roommate's hand while something tries to get into their bedroom. When the lights come on, her companion is across the room and something is still holding her hand. SHUDDER.