How to Train Your Dragon (animation)/Tear Jerker

Examples from the film

• Toothless' first scene.
• When Hiccup wakes up and discovers that he's lost his left leg in the battle; it's even more jarring if you didn't hear Gobber imply it earlier. Not to mention, the part Hiccup tries to walk using his artificial leg and immediately stumbles is like an emotional kick to the groin.
  • Followed immediately by the most heartwarming moment in the movie, when Toothless catches him and gives him a look that just screams "You helped me, now I'll help you." Fire-Forged Friends, indeed.
• The scene where Stoick disowns Hiccup. Hiccup pleads for him to listen for once in his life, is thrown back and told "You're not my son". Hiccup's face as he watches his father leave really helped the tears flow, as does Stoick's expression after the door closes behind him.
• Stoick mourning over his son's apparent demise in the aftermath of the fight with the Red Death. Granted, we all knew Toothless saved him somehow, but the sheer despair and sorrow in Stoick's voice as he grieves over the loss of his only son feels like a punch to the gut.

Stoick: I did this.

• Test Drive, strangely enough. There's just so much adrenaline and emotion that it gets kind of overwhelming.
• The scene in the training ring, right after Toothless rescues Hiccup. He looks so proud of himself and keeps looking back at Hiccup to see whether Hiccup was impressed by his fight, while Hiccup is so terrified that the swarming Vikings will kill Toothless.
• In "Gift of the Night Fury", when Hiccup builds Toothless a completely working tail. When Toothless realizes he can fly independently, he backs away from Hiccup and takes off.
• The sequel "How To Train Your Dragon 2" is full of even more moments that will make you bawl your eyes out:
  • Stoick sacrificing himself and taking a deadly plasma shot from a mind controlled Toothless that was meant for Hiccup which costs him his life, Toothless snapping out of it wondering what he's just done only to be shouted at by a grief stricken Hiccup to get away and then Drago takes Toothless for himself. What's worse is that if Hiccup actually listened to Stoick from the beginning none of this would have happened.
  • Stoick's funeral
  • Valka showing Hiccup the dragons that have been seriously injured by Drago and his trappers. One has lost leg to an iron trap, another has a torn wing from razor netting and one is blind from a tree snare which was also left to die alone. 
  • The flashback of Valka being taken by Cloudjumper as Stoick while holding a baby Hiccup sees his beloved wife being taken before his very eyes and there's nothing he can do about it.
  • Drago Bludvist might be an asshole but it's not hard to feel some form of pity for him the minute he takes off his arm revealing he lost his real one, saw his entire village burned and saw his family die all to dragons when he was just a boy. Although we never directly get to see what happened to Drago's village it's very obvious he would have been absolutley terrified and traumatised by all of this. The more gentle but somber music that plays as Drago talks about this makes it even sadder to show that Drago has a layer of tragedy to him. Even Djimon Hounsou the very voice of Drago himself said in an interview that Drago is a torn soul that has been really badly hurt.