At the 39-40 minute mark, Seth bends over to look under his bed to see if Summer took his comic book drawings. When you see him bend down, he puts his right hand on the floor to give him stability and from another angle it is his left hand on the floor, and back and forth.
In the scene in Seth's bedroom with Seth and Summer, there is a white fluff on the back of his sweater that appears and disappears between shots.
Sandy's old law professor says that he moved from Berkeley to Princeton. Princeton has no law school.