In this picspam I'm going to compare a few scenes were Blair and Chuck hurt each other. I know that there are more scenes than these, but I'll post them in another picspam.
1x13 "The Thin Line Between Chuck and Nate" & 2x15 "Gone With The Will"
2x14 "In The Realm Of The Basses" & 2x19 "The Grandfather"
EDIT: I took away the comments below each picture because after reading them again some of it just sounded silly. And besides the pictures describe the scenes pretty well.