Why did everyone like Mr. Bingley?

Mr. Bingley has many admirable attributes. The "second-hand intelligence" of Lady Lucas, given because Mr. Bennet was unable to provide any satisfactory information about the gentleman, was that Bingley was young, handsome, "extremely agreeable," and moreover was likely to be attending the next large gathering in the area. This pleases the Bennet girls because a fondness for dancing "was a certain step towards falling in love," so all in all Mr. Bingley seems a heartening prospect.
When they actually do meet Mr. Bingley, the Bennet girls agree that he is "good-looking and gentlemanlike," with a pleasant face and "easy, unaffected manners," meaning that he comports himself well and does not, unlike the handsomer and wealthier Mr. Darcy, put anyone off with his behavior. On the contrary, Mr. Bingley dances with everyone in a "lively and unreserved" fashion and suggests possibly giving another dance of his own at Netherfield later on. In contrast to Mr. Darcy, Mr. Bingley looks all the more impressive in character, because Darcy, "the proudest, most disagreeable man in the world," dances only twice and does not wish to be introduced to any of the other ladies present, choosing to keep to himself instead.