The Catillac Cats episode "Christmas Memories", has Leroy depressed because nobody remembered his birthday, and it also dawns on him that he really doesn't have any friends. He then gets lured to a party by the Catillac Cats, which just happens to be his own birthday party. At the end of the episode Leroy acknowledges, despite all the times he's tried to chase them out of the junkyard, they're the closest he has to companions.
The ending to the episode "Terrible Tammy" where Sonja protects Heathcliff and even defends him from getting attack by Tammy. Previously she though Heathcliff was hanging out with Tammy but later hears about her boasting about the terrible stuff she's been doing including thinking she liked him more than Sonja. She even decides to apologize and makes it up by beating her up since Heathcliff refuses to attack her since she's a girl.