STRONG BAD:
He thinks he's great.
Strong Bad's lackey, and probably his best friend. Strong Bad doesn't treat him very well, though. He kicks him all the time.
The only other character Strong Bad legitimately likes. Although they don't always get along so great.
Strong Bad idolizes Senor Cardgage, but gets creeped out by him sometimes.
Strong Bad hangs out with Pom Pom and thinks he's cool, but he doesn't like him the best.
Strong Bad is neutral towards Bubs.
Strong Bad generally seems to dislike Coach Z, but they get along occasionally, making rap videos and such.
Again, disliked by Strong Bad, but they get along at times. Not as much as Coach Z, though.
Strong Bad hates Homestar. But they also hang out a lot and have some conversations, which Strong Bad usually doesn't do with other people he hates. This shows that he tolerates Homestar.
Strong Bad rarely gets along with the King of Town.
Even less with the Poopsmith.
And even less with Homsar.
Who Strong Bad hates the most, subjecting him to frequent pummelings, belly-buttonings, and death-wishenings.
HOMESTAR RUNNER:
Homestar's best friend. Need I say more?
Homestar thinks Strong Bad is his friend. He goes to his house a lot, too.
Homestar's girlfriend, but he doesn't respect her all that much. "Hey stupid, I brought you this stuff!"
They have friendly conversations and give each other advice. But Homestar seems to think Coach Z is at least slightly creepy and depressing.
They seem friendly toward each other.
He is generally quite friendly toward Strong Sad (them being in the Wet Knee Gumption Club, for instance), but also unfriendly (interrupting him, ignoring him, not believing he exists).
He generally tries to get along with The Cheat.
He likes the King of Town, and they help each other out sometimes.
Homestar rarely shows signs of liking Strong Mad, but he clearly doesn't mind him.
He doesn't mind the Poopsmith, and thinks he's a good guy.
He frequently thinks he's a different person, and he insults and fights himself sometimes as a result.
They rarely interact, but Homestar doesn't seem to like him much ("Oh, the secret guy"). But he tolerates him, and has even called him Homestar once.
Homestar has hardly shown any kindness toward poor Cardgage, only telling him he smells like pea soup.