Watch this crucial exchange between Penny and Will where it all comes to a head:
Penny: Maybe it is love, as much as it can be, for somebody...Watch her face as she reacts to this piece of information. The tears that come unbidden, held back for a moment, the brave smile, and the response: What kind of beer?
William: Somebody who sold you to Humble Pie for fifty bucks and a case of beer! I was there! I was there!... Look- I'm sorry.
If that doesn't deserve an Oscar nomination, I don't know what does.