In "Communication Problems", the one time the show gets you on Basil's side, because his obnoxiousness is fully justified as he's standing up to an insufferable and dishonest persnickety customer.
Mrs. Richards: When I pay for a view, I expect something more interesting than that!
Basil: That is Torquay, Madam.
Mrs. Richards: Well, it's not good enough.
Basil: Oh? And may I ask what you were expecting to see out of a Torquay hotel bedroom window? Sydney Opera House, perhaps? The hanging gardens of Babylon? Herds of wildebeests sweeping majestically—
Mrs. Richards: Don't be silly. What I wanted was a view of the sea.
Basil (pointing): You can see the sea. It's over there between the land and the sky.
Mrs. Richards: I would need a telescope to see that!
Basil: Then may I recommend you try moving to a hotel closer to the sea! Or preferably in it.
Mrs. Richards: Right, now, listen to me: I'm not satisfied. However, I have decided to stay here. But I shall expect a reduction.
Basil: Why? Because Krakatoa's not erupting at the moment?
Another example of a guest being so much more ruder than Basil that we're completely on his side is the bratty boy from "Gourmet Night," and dear lord is he on a roll this time:
Boy's mother: He's very clever, rather highly strung.
Basil: Yes, yes, he should be.
Boy: (about his chips) They're the wrong shape.
Basil: Oh dear, what shape do you usually have? Mickey Mouse shape? Smartie shape? Amphibious landing craft shape? Poke-in-the-eye shape?
Boy: (about the mayonnaise) That's puke, that is.
Basil: Well at least it's fresh puke.
- Oh and to top it off, he gives him an "accidental" slap on the head too.