Continuity mistake: When Buffy is talking to Riley, she puts the scarf on her head, on his hand. He talks to her and says "Maybe I am the bad guy," and in the next frame her scarf is back on her head again, then off again in the next frame. (00:24:20)
Beware the Third Wish - S1-E31
Continuity mistake: The Wicked Wisher throws giant exploding coins onto the field TJ is on, as TJ runs towards the WW. The giant coins remain on the field after they explode, yet when TJ reaches the top of the field, there is no sign of the coins, or their remains.
Continuity mistake: The fish that Harley uses to protect herself from the Joker changes shape and size every shot.
Continuity mistake: His Shadow does "the kiss" and transfers his soul into the new host with the Clerics. As they are lifting the new host back up, the shot cuts and suddenly two Clerics appear behind him. (00:16:10)