Continuity mistake: Right after Budd shoots Beatrix, he kicks her sword away from her, but the sword keeps changing position in subsequent shots. Sometimes it's on the ground and sometimes it's stuck in the side of a trash can. (00:25:30)
Continuity mistake: When Bill is cutting the crusts off a sandwich towards the end, he cuts two off, goes to remove the third, then the angle changes and he's now cutting it in half. After that we hear him sweep the crusts off the board and see him hand the sandwich to BB, then a shot or two later crusts are back on the board and he cleans them off again to make another sandwich. (01:29:05)
Continuity mistake: In the scene where the diner owner sees Beatrix walking towards the diner after getting out of the graveyard, you can see a CLOSED sign in the window and is pushed to the left corner of the window frame. When Beatrix is walking in you can see the same sign in the left window but is right up against the right of the window frame. You can actually see by the green pipe outside the diner that they have changed the sign's location. In the first shot the green pipe is outside the window. In the following shot where you can see the sign in the left window, the green pipe is outside the right window. (01:00:10)
Continuity mistake: When Budd looks at the case of money, the left column of money lies vertical. In the following shot it is now horizontal. (01:06:40)
Continuity mistake: Right at the beginning of the scene where The Bride is fighting Elle in Budd's trailer, Elle swats her back towards the back of the room with the sword. The Bride then takes one of the TV antennas as a weapon; notice the green bottle of beer on the TV. As she yanks out the antenna, she hits the beer bottle which falls. In mid-fall, however, the shot changes and the bottle is back on the top of the TV again. (01:14:20)
Chosen answer: The way she talks to Budd as he lies dying, seems to indicate that she has disliked and hated him for years, plus the fact that she feels that he was not "worthy" of killing Kiddo (seeing how Kiddo was a fantastic warrior, while Budd is an alcoholic hick). However, it would be difficult for her to get close enough to kill him earlier, as he would not buy any excuse why she just came visiting. But when Budd actually invites her over, she gets a chance to get back at him, and in the same while take the credit for killing the Bride and retrieving her Hanzo sword for Bill. Vengeance and personal gain in one swoop.
Twotall