 Why does Lester want to kill himself?
Apparently, Lester doesn't realize that snipped roses are garden-variety symbols of castration, or he'd know what he has lost. Ambient noise falls away, the crowd disappears, and there she is, Lester's angel, writhing in slow motion--just for him. Later, Lester envisions her on a bed of red petals, then immersed in a bath of red petals. Lester's wife, Carolyn, is even more stridently caricatured. Ricky speaks of glimpsing in the bag's trajectory an "entire life behind things"--a "benevolent force" that holds the universe together. The teen-ager, who likes to train his lenses on dead bodies of animals and people, sells wildly expensive marijuana to Lester and somehow passes on this notion of "beauty."
 He feels lost.
 He feels he completely failed at life.  He hates his wife.  He is attracted to minors.  He feels lost.