Continuity mistake: When Angel and Buffy are sitting down talking about their kiss, Buffy picks up a coffee mug and holds it with both her hands. But in a wide shot shortly afterwards, she is no longer holding the mug and it has moved further down the table.
Factual error: According to the show, Angel learned quite a few languages when he was evil. However, when he tries to start a conversation with a red-faced demon, he makes terrible mistakes. He said "Hablo Espanol?" which literally means "Do I speak Spanish?" and he said something like "Are you from Byelorussia?" in a tongue that hardly resembled Russian, although according to the captions, it was said in Russian.
Add timeGrigory the Wanderer
Revealing mistake: In "To Shanshu in LA" in season one, as Angel is pulling out of parking lot to follow the W&H Trucks, you can see his reflection in his rear view mirror (vampires have no reflections). Also odd that throughout the first season the rear view mirror is removed in some episodes.
Continuity mistake: In Season One Finale, "To Shanshu in LA" when Wes is lecturing Cordy on wants and desires, the number of bites taken from the doughnut changes, in one instance it breaks in half, most visibly when Wes takes a bite from Cordy's doughnut on the angle change.
Continuity mistake: In the season one finale "To Shanshu in LA," near the end Angel is fighting Vocah in the mausoleum and Angel rips off Vocah's mask, revealing the maggoty face underneath. In subsequent shots of Angel from behind Vocah, you can still see the edges of the mask on his face.