Oh, now I get it (maybe).

Rating: 10/10 (7 December 1999)

(Spoiler alert)
I've read everyone of these comments and even made one myself. This movie has constantly been on my mind since the day I experienced it. To commend the actors at this point would be redundant, and that's not what I want to say.
And I'm probably wrong here, but this is what I now perceive.
Lester could not make the leap to maturity, he had hit a wall. In the face of failure he regressed into a comfort zone he had once enjoyed. He was taken by the beauty and earthiness of Angela and she became his all encompassing desire. When the opportunity presented itself to fulfill this desire, reality set in. At this moment he made the leap into mature adulthood.
He sat down and savored the family he really loved.
And we all know what happened then. And his closing words, "Don't worrying, you will," ring true. He really truly relished being alive. You and I should too.