In 'The Kipper and the Corpse', Basil escapes all consequences by climbing into a laundry basket while his wife is left to mop up his mess. Cue end of episode. Refuge in Audacity, obviously.
Throughout the series, getting Sybil angry is a very large worry. Considering her reaction when she finds out about the construction folly in episode 2, this is a very, very, very justified worry. Sybil the dragon faced with an optimist... She can kill a man at ten paces with one blow of her TONGUE!
Sybil: We have used O'Reilly three times in the last year and each time it has been a fiasco! That wall out there is still not done! You had him in to change a washer in November and we didn't have any running water for two bloody weeks!
Basil: Well he's not really a plumber, dear.
Sybil: Why did you hire him? Because he's cheap! And the reason he's cheap is because he's no bloody good!
Basil: You never give anyone the benefit of the doubt! He's not brilliant...
Sybil: Not brilliant? He belongs in a zoo! He's shoddy, he doesn't care, he's a liar, he doesn't care, he's incompetent, he's lazy and he's nothing but a half-witted, thick Irish joke!
Basil: Hello O'Reilly, we were just talking about you, and then we got on to another Irish builder we knew. God, he was awful!
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?
Likewise, the end of the hotel inspectors episode, where after dealing with the insufferably picky Mr. Hutchinson for the entire episode, finally just slams two cream pies into his face and crotch, pours a pitcher of milk into his briefcase, and throws his prissy ass out the door.
Basil: And if you ever come back, I shall kill you.
John Cleese once said that the only thing he didn't like about that scene was that the screams of laughter from the studio audience drowned out that last line.
Another example of a guest being so much 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.
In the anniversary episode, Polly finally gets tired of Basil dragging her through insane scheme after insane scheme, gives him a "The Reason You Suck" Speechand forces him to pay her out the nose before agreeing to any further plans.
While it ultimately backfires badly on him, Basil within another rant from Sybil, quickly silences her with a firm Big "Shut Up!" in "The Psychiatrist".
Basil: I'm fed up with you, you rancorous, coiffured old sow. Why don't you syringe the donuts out of your ear and get some sense into the dormant organ you keep hidden in that rat's maze of yours?
One of the rare times a guest has a Moment of Awesome over Basil; Basil is not happy about having a Cockney chap by the name of Mr. Brown in his hotel, especially since he is now advertising to the higher classes. He believes Mr. Brown to be an idiot, even going so far as to patronisingly add that Barcelona is in Spain, when explaining the communication problems with Manuel. When said communicaton problems begin as per usual, Mr. Brown turns around and explains the request to Manuel in fluent Spanish, much to Manuel's delight. Of course, Basil won't admit to his snobbery and it turns out Mr Brown is from the CID, but it's nice to see Basil's rudeness get shot down when it's not called for.