James Cameron's record-breaking 1997 smash about icebergs, death and appalling Cockney accents. You may remember it.
Mark interviewed Leonardo diCaprio for The Beach (2000) and opened with the words "I forgive you for Titanic." Mr diCaprio was, apparently, somewhat nonplussed. Mark then interviewed him sometime later for The Aviator, and repeated the line. That's how much forgiveness Leo needed.
The film also taught Mark a valuable lesson about audience demographics, which often gets related during discussions of Twiglet. Mark once spent quite some time berating a representative from one of the studios that had made the film, explaining to her exactly what was wrong with it - the plot, the dialogue, the sentimentality porn. She patiently listened until he was quite finished, then looked up at him and said "your problem is, you're not a teenage girl."