Here's why... picture the scenario: you offer her a drink, she says yes, you go to the bar to buy two drinks (one for you, of course), you come back, she's talking to some other guy.
You, in effect, are some schmuck standing in a bar with two drinks in your hand.
There are a ton of guys who don't mind being the schmuck. Don't be one of them. Keep talking to the girl." -Scott