Mostly 'cuz Chosen makes me sob beyond belief, and there are a couple other eps that get me teary-- Selfless, Showtime, Touched, Dirty Girls to name some. There are a ton of episodes scattered through the rest of the seasons that make me bawl as well :(

the season 5 finale makes me cry my eyes out

I cried so hard while seeing 'The Body' and off course Buffy dies at the end of this season

I cried alot when Buffy died in the season 5 finale.

Its between 2&5 for me. Two because of passions and becoming part 2 but season five tops it with Joyces death, Riley leaving (even though i love Bangel, I thought it was quite sad) and of course Buffys death!

Passions makes me cry, and Becoming part 2, even though I'm a Spuffy fan I cry at the end because I feel so bad for Buffy.

Tara's death, and Xander leaving Anya at the alter

Tara's death was so sad. :-(

I cried when Buffy died.

seasons 2, 5 and 6

When Joyce and Buffy died

and season 2.

When Joyce died that was so sad! and also the end of season 5.