What's one difference between modern and Greek tragedy?

There are, of course, many differences between modern and
Greek tragedy.  Here are several of them:

1. Greek
tragedies involve a Chorus. The Chorus often provides background detail, poetic
elements, and summaries of events in between scenes. Sometimes the Chorus serves as a
type of moral judge over characters' actions and words; Sophocles' Antigone
is a good example of this type of Chorus. Modern tragedies do not have a
chorus or really anything similar to it.

2. Modern
tragedies in written form provide readers with stage directions and usually detailed
descriptions of the play's sets. While the Greeks did use masks to show character
change, they performed their tragedies on a bare stage, where elaborate sets would have
been insignificant even if they were available.

3. Most
importantly, while Greek tragedies feature their heroes or heroines realizing their
flaws and sometimes repenting of them, modern tragedies often do not. In Death
of a Salesman, a modern play, Willie Loman commits suicide, but it is not the
noble death of a Greek tragic hero; rather, he takes his life out of hopelessness.
Admittedly, many Greek tragic heroes commit suicide, but they do so after realizing that
their flaw has brought down them and the ones they love--their deaths would have been
viewed as moral and noble by an Ancient Greek audience.