The dash helps to indicate that the two thoughts are intimately related, and it's less stodgy than a semicolon, which would have performed the same function (and who talks in semicolons?).

Champions behave like champions before they are champions

When I give a speech at a corporate event, I often ask those in attendance, 'Do you know how to tell if you're doing the job?' As heads start whispering back and forth, I provide these clue: 'If you're up at 3 A.M. every night talking into a tape recorder and writing notes on scraps of paper, have a knot in your stomach and a rash on your skin, are losing sleep and losing touch with your wife and kids, have no appetite or sense of humor, and feel that everything might turn out wrong, then you're probably doing the job.'

The dash helps to indicate that the two thoughts are intimately related, and it's less stodgy than a semicolon, which would have performed the same function (and who talks in semicolons?).

Everybody's got an opinion. Leaders are paid to make a decision. The difference between offering an opinion and making a decision is the difference between working for the leader and being the leader.

Machines aren't replacing proofreaders at all. Copy editors, who proofread and much, much more, use spellcheck as a tool but read every word that appears in the paper

We have a lot of players in their first year. Some of them are also in their last year.