1) Larkspur dressed up for Applejack and Rarity's wedding. Of course wearing orange, his dad's favorite color.
2) "Aww…did you come just to say hi to me?"
After Discord left, and Fluttershy became kind of an emotional wreck, Larkspur lost his friends after bringing his pet rattlesnake to school. It ended up biting someone, and the other kids began avoiding him in obvious fear. He starts lashing out for all of the abandonment he's experiencing at once, and as a result, he had no more friends. So he was alone throughout his childhood. However he never loses his touch with animals, and one day while crying alone outside, a friendly tarantula hawk stops by to comfort him.
3) As Larkspur ages, he loses all sympathy for others. He develops into big bully, even after he's enrolled in Twilight's school, and basically becomes the local prankster asshole. Everyone hates him, and he liked it that way because any attention is better than none.
4) Larkspur was the first child born among the mane six, so imagine their joy when they finally got to meet their best friend's baby. Lot of crying and overly saccharine happy stuff.