Heartwarming / Scooby-Doo and the Alien Invaders

• As sappy as "Groovy" is, it's just so sweet and perfect in showing how smitten Shaggy is with Crystal that you can't help but gush about it. Some particular moments:
  • Shaggy sings about how he'd face it all for the girl he's fallen for, and it means a lot to hear it from someone who's such a Cowardly Lion.
  • Shaggy also implies he's delighted to meet someone who's just as crazy about groovy old stuff. Given the movie's modern setting, it comes across as the dated fad it's regarded as in real life, but Shaggy has found someone who still loves that stuff herself.
  • While expecting Crystal to cook enough to feed his massive appetite is silly, from his perspective, Crystal would love him despite the massive intake he has when usually everybody teases him for it.
  • The tie-dye wedding, specifically Fred, Velma, and Daphne attending happily and being a best man/groomsman and bridesmaids. Shaggy may have love on his mind first and foremost, but he still loves his friends and still imagines them as part of his special day.
  • Shaggy Junior is a cute thought, even if it's the idea of having a baby with someone he met a few hours ago. Scooby and Amber's puppies, though? Admittedly still kinda rushed, but nothing short of adorable, especially the idea of them being raised alongside Shaggy Jr. and having the same family bonds.
  • And finally the "Don't forget Scooby-Doo!". It shows that, even in his whimsical fantasies about an idealized future with a woman he's crushing on, Shaggy will always have room in his life for his best pal.
• Velma and Daphne are very supportive of Shaggy and Scooby's feelings for Crystal and Amber. They even show sympathy for when Crystal and Amber have to leave the Earth and can't be with Shaggy and Scooby.
• Despite being rather gruff and rude to the gang for most of the movie, Buck proves to be a genuinely a sweet-natured guy, and it's revealed that "a little hobby" of his is collecting and pressing flowers — he shows Fred and the girls one book he has, and they note that the flowers he has are very beautiful and agree to keep this a secret (as Buck explains to them that it's something he prefers to keep quiet about).
• Lester giving the gang a place to stay when they're stuck in town.
• Shaggy and Scooby's awed view of the night sky.
• Amber's reaction to Scooby bringing her flowers.
• As ruthless and cruel as they can be, the bad guys seem to have a decent Villainous Friendship, with Steve telling Laura to go free the others while he's fighting Crystal and Amber, as well as bothering to help Laura up -when she's knocked down and covered in oil- before trying to escape himself.
• Fred comforting a depressed Shaggy and Scooby is heartwarming even when Scooby says "destroyed" Fred sympathetically bends down and pets him assuring him they'll move on eventually.
• Despite how heartbreaking it is, Crystal and Amber ensure Shaggy and Scooby know how much they mean to them and both given them a goodbye kiss (sadly Shaggy and Crystal's only one). Amber and Scooby's final words to each other are both upsetting and very heartwarming.
  (sad Held Gaze)
  Amber: Goodbye, Scooby. I'll never forget you. ''(kisses him on the mouth)
  Scooby (blushes) Me too, Amber.

---