I am convinced that they are the same movie. This is only version 1.0 of this theory. (I also see Brad Pitt's 12 Monkeys character as a predecessor of Tyler.)

Really. Think about it - they have several common themes.

• rejection of life in corporate America
• too much stuff
• isolation

rejection of life in corporate America

An ordinary man, stifled by life in corporate America, passes through disillusionment and out through the other side. Fight Club advocates destruction of corporate America in order to return to what is truly essential. American Beauty, on the other hand, advocates a strategic withdrawal, first from corporate America, then from everything else, until you locate your misplaced self.

One is antagonistic, one is pacifistic. One is violent, one is passive. One preaches the company of men, and proclaims that for a generation of men raised by women, another woman is not the answer. One embraces love and sexuality as part of the human experience.

In fact, that may be the defining difference between the two stories. Fight Club is extremely masculine - the only female character is more masculine than at least two of the male characters. Lester in American Beauty, on the other hand, is surrounded by women and their influence.

Maybe that is it. The same movie for two kinds of men in the world: those who live in world without women, and those who live in a world with women.

isolation

Tyler and Lester are both very alone in the world -- neither one has any friends. Neither one has a real social life. At the beginning, Tyler attends support groups to find an emotional connection/outlet. Lester has shut down almost completely.

too much stuff

Tyler:
The things you own end up owning you.
We work at jobs we hate to buy things we don't need.

Lester:
This isn't life! This is just stuff. And it has become more important to you than living. And honey, that's just nuts.