wow, there are a lot of tear jerking moments. i guess we can take it a season at a time.
season 1-prophecy girl "i dont wanna die" breaks your heart to hear her fear.
season 2-innocence buffy having to come to terms with the man that she loves is gone, passion jenny's death, and the way it was set up, was just so cruel. your heart really breaks for giles, becoming it breaks my heart every time i watch it. i cant help but cry when i watch that ep.
season 3- amends the end when buffy gives the speech to angel about how it would be easy if she could wish him dead, it gets me every time. the prom the class protector speech, and angel showing up for the dance.
season 4- wild at heart it made me so sad when oz left.
season 5- family at the end when mr maclay asks who they are, and buffy replies with family, its so sweet i cry. yes i am a baby. into the woods as much as i hate riley, and was so glad to see him go, it was a sad episode because you could feel buffys pain as she tried to catch him before he left. but im still glad he was finally gone. the body enough said. the gift buffy leaping off the tower, and the words she shared with dawn before she did so. my favorite quote ever, "the hardest thing in this world is to live in it, be strong, live"
season 6- tabula rasa while one of the funniest episodes of the series, ending is sad, with tara and willow splitting up, and giles leaving to michelle branch's "goodbye to you" makes me cry. hells bells you really feel for anya being left at the alter, a nightmare for any woman. seeing red/villians taras death. grave xanders speech to bring willow back.
season 7- help cassies death, was just so sad and she wasnt even a recurring character. potential xanders speech to dawn about how special she is, and how hard it is to be on the sidelines. the killer in me not sure why, but that ep gets to me. empty places buffy getting kicked out chosen the end. the whole episode is sad to me, i even cry during the speech about making all potentials slayers, im just a big sap.
and thats just what i could think of off the top of my head. im sure there are more.