Love
Jim is the love of George's life. Ironically, when Jim is killed in a car accident his family will not call to tell George because of their homosexual relationship.
Last Day
George sees things in a heightened way as he makes his way through his day. Ironically, it is because he knows this is his last day on earth and thus every experience is his last.
Sleeping Bag
George is about to pull the trigger after having zipped himself up into a sleeping bag on his bed. Ironically, the phone rings. It's Charley asking where he is for dinner. Saved by the bell.
Substitute
Charley says that George and Jim's love was a mere substitute for the real thing that he could have. Ironically, their love was very real, lasting, while hers to her husband was not. Yet she tells George what he should have.
Around the Corner
George goes just around the corner to get a drink and a pack of cigarettes from his local bar just before he is going to kill himself. Ironically, Kenny, his student, shows up and they spend the night together, a night which convinces him to live.