Clannad When Nagisa and Ushio die also the whole Fuko thingy
Sword Art online When Yui "dies" and when Asuna and Kirito "die"
Tokyo magnitude 8.0 This anime made me cry like a little baby all the time, especially when Mirai realises that Yuuki died. Ugh and when Mari and Mirai were reunited..
Hotarubi no Mori e ending
Angel beats ending
Samurai Champloo ending
I also cried when I watched the last episode of Black Lagoon
The grave of the fireflies the whole movie is about making you sad