Glengarry Glen Ross

It is not for no reason that all of the cast of characters in Glengarry Glen Ross is male.
The play uses the male psyche as a canvas on which to portray a number of the ills of the human condition: egotism and deceitfulness (as exemplified by the majority of salesmen in the play) on the one hand; the impotence and depressive servility of Jim Lingk on the other. Though the play admittedly covers a broader range of emotions than that simplified dichotomy -- the weariness of Aaronow, the office's odd man out, comes to mind -- those two extremes are what the play contrasts the most overtly.
It seems to me that the target of Mamet's scorn, rather than being simply the businessmen in and of themselves, is the culture which gave birth to them. Part of this comes through in Aaronow's last statement in the play: "I hate this job." His hatred is not for his co-workers, but for their profession, for the rat race and its treachery. The line that follows it -- Roma's statement that he will be "at the restaurant," his hunting grounds where he can sell so well -- suggests that even after the ransacking of the office, Roma will still continue to do what he always does best: closing, taking advantage of those with weak defenses. In other words, the salesmen's work does not end with the play.

King Lear

King Lear is my third academic encounter with Shakespeare, coming at me after Julius Caesar in my sophomore year of high school and Othello in my senior. (I wrote a decent paper in ENGL1102 last year on Antony & Cleopatra but, I confess, did not actually read the play.)
Personally, I've always been on good terms with the Bard. The literature of his era is not, generally speaking, what really piques my interest (though I certainly do not consider myself a time-period-specific reader), but Shakespeare -- both his drama and his poetry -- still intrigue me. I think this is the case for the same reason that he has endured so well and is taught (with varying degrees of reluctance or enthusiasm from those on the receiving end) so widely across the board, on so many levels in the world of academia.
King Lear the character seems to be very polarizing. The reader either sympathizes with him, or hates him. I would say something similar to a comment I remember making in class about The Moviegoer -- that it is precisely that ambiguity and that ability to make the reader feel strongly in one of a number of ways that is Shakespeare's strength. It's not a sign of weak writing. That ambiguity is more true to life, then as it is now.
Also, it's interesting in the fact that, besides being the achievement of Shakespeare, the feelings of the reader towards Lear often says more about the reader than Lear or Shakespeare.
And, really, that is what [enduring] literature does: it shows us ourselves.