Darcy's best friend is a nice guy who is a little too easily manipulated by his friends.
Before we really dive into Bingley, go back and reread Book 1, Chapter 10, when Darcy and Elizabeth have their first long conversation. We'll wait.
Ready? OK, did you notice how much philosophizing there was? It's like that any time they have a conversation – just lots of abstract thinking about the way people are supposed to behave. In this case, they are talking about just how much someone should be influenced by what his friends want him to do. Darcy says not at all, while Elizabeth plays devil's advocate (we're guessing, since she's so pigheaded it's hard to imagine her doing anything just because a friend told her to).
What does all this mean? Well, it's a pretty good way to set up the character of Jane's love interest, Charles Bingley, who is about as spineless and indecisive a man as could be. However much in love with Jane he is, as soon as Darcy tells him to pack up shop, he does it. As soon as his sister and Darcy tell him that Jane isn't really that into him, Bingley is ready to buy it. Amazingly enough, if Darcy never told Bingley to give Jane another shot, Bingley would never have gone after her again. Considering how overly nice Jane is, it's sort of hard to imagine how they will manage their lives together, isn't it?Mr. Bingley Timeline