Harry Potter and the Sorcerer's Stone
How we cite our quotes:
"Go on, have a pasty," said Harry, who had never had anything to share before or, indeed, anyone to share it with. It was a nice feeling, sitting there with Ron, eating their way through all Harry's pasties, cakes, and candies (the sandwiches lay forgotten). (6.171)
This tells us right away that Harry is, deep down, a good and generous person. Living with the Dursleys hasn't drummed all the morals and values out of him. At the first opportunity to participate in sharing, that's exactly what he does. He's rewarded with the "nice feeling" of a shared meal and also with a good friend for life.
He turned back to Harry. "You'll soon find out some wizarding families are much better than others, Potter. You don't want to go making friends with the wrong sort. I can help you there." (6.244)
Funny how certain individuals are convinced about who is the right and "wrong sort," and stick to their ideas with passionate conviction. Here, Malfoy shows his prejudice by discriminating between pure and mixed-blood "wizarding families." He implies that you should make friends with people just because of their family background. What's ironic about this is that, just as Malfoy judges others for being the "wrong sort," people like the Dursleys would judge him as the "wrong sort," based on the idea that he can do magic at all.
"Look!" said Malfoy, darting forward and snatching something out of the grass. "It's that stupid thing Longbottom's gran sent him."
The Remembrall glittered in the sun as he held it up.
"Give that here, Malfoy," said Harry quietly. Everyone stopped talking to watch. (9.40-42)
The term's just barely started, and the first-years are taking sides and forming alliances already. Harry's not going to let Malfoy get away with taunting a fellow Gryffindor (Neville), while Malfoy's capitalizing on the beginnings of Harry's friendship with Neville to really just get to Harry.