Spike - becomes slightly less of a loner or at least more tolerant of his companions. While at first Faye, Ed and Ein were nothing more than inconveniences at the end of the day it's obvious he does care about them. He also works out his past.
Jet - becomes closer to Spike and really takes on a father figure role
Ed - well... okay, maybe not. Ed is Ed. Though she does come to realize that family is important.
Faye - the most character development. We learn that Faye is not just a tough girl but a woman who got burned and is lonely but too afraid to get close to anyone. Her final goodbye to Spike and the way she deals with her past says the most about how she's changed.
I know you're just trolling but it's a bit of a pet peeve.