The song's power lies in its acknowledgment that the life of dissipation must be temporary to have any value. Dissipation must be in contrast to real life - it must be the shadow against which real life shines, not the screen that real life is shown upon.

Margaritaville is analagous to college life: it is temporary, it isn't real life. Hanging in Mexico for a while is even better than college: you don't have to study. Dissipation and languor are accepted ways of life in college AND in Mexico, but someone has to pay for college, and even Mexico requires some outlay of cash. Depletion of funds give college and Mexico their natural ending for most people.

A musician like Jimmy Buffett has sufficient royalties coming in to sustain this lifestyle indefinitely, so he must create his own ending to the story. It is his progress toward that ending that gives the song its drama:

"Nibbling on spongecake,
watching the sun bake
All of those tourists covered with oil,
Strummin' my 6 string,
on my front porch swing
Smell those shrimp they're beginning to boil."

This sounds to be paradise incarnate: all needs met, no demands made. The singer's voice tells us otherwise, though. He is bored, played out and can barely rouse himself to mumble the words o fthe chorus:

"Wastin' away again in Margaritaville
Searchin for my lost shaker of salt,
Some people claim that there's a woman to blame
But I know its nobody's fault."

All of the seduction and the resignation and the hopelessness of addiction are there in Buffett's voice. He knows he's "wastin' away." He can't even get it together to do the Margarita right anymore; he isn't even bothering with an excuse. His addiction has become, in Lou Reed's words, "his wife and his life." What began as a pleasure, a diversion, has become punishment for overindulging in that pleasure.

"Don't know the reason,
I stayed here all season.
Got nothing to show but this brand new tattoo
But its a real beauty,
a Mexican cutie
How it got here I haven't a clue."

Reckoning is in the air though because Buffett ends the 2nd chorus with:

"Some people claim that there's a woman to blame,
Now I think, 'hell, it could be my fault'."

Responsibility is an awesome weight but ultimately it cannot be imposed upon us from without. We must accept it for what it is: the demand to live up to our own values. Clearly, the singer's lifestyle here doesn't coincide with his values. Rather than living a life of ease, he is living a life of intense internal conflict, a life he can only perpetuate with liberal applications of alcohol. He doesn't even want to face up to the fact that he is drinking alcohol. He disguises the alcohol with mixes and rituals - rituals that are fast wearing thin.