In "Martha's Life in Crime, part 1", little Helen runs around the house screaming "yay!" because her parents give in to let her have Martha.
Martha and Helen together for the first time in "part 2".
In "Martha's Thanksgiving", Martha and her siblings reunite with their mother.
Skits realising that he's unique in "Martha and Skits".
When Martha finally makes friends with Kitten.
And her speech in that episode
Martha: "You don't know anything about him! You're just being prejudiced! Yeah, prejudiced! Like when you decide you don't like someone before you even know them! You prejudge them! I used to be prejudiced, too, but Skits, there are good cats. And there are not-so-good cats. Like there are good dogs and not-so-good dogs. Just give him a chance!" Doubles as Awesome.
When Skits gets forgiven in "Martha and the Thief of Hearts". And then everybody else gets forgiven.