BtVS - A Continuity Error That Drives Me Crazy

 In Seeing Red, Spike leaves his coat on the stairs at Buffy's house, but in Get It Done he goes to the school basement to retrieve it. I know the obvious explanation is that Buffy brought it to him, I feel like if she did this is something that should have happened onscreen.

 

Are there any continuity errors that really bother you, even though they are easily fanwanked?