This is the first time I remember laughing hysterically at something I had seen on TV. I remember laughing uncontrollably, crying with laughter, and gasping for breath. I had never seen anything like it before. If you've not seen it, this is the moment where after a string of unfortunate events Basil Fawlty's car breaks down and he ends up hitting it with a stick.
There are so many aspects of this sequence which lead to it being as funny as it is, but on the other hand, it is simply a moment of pure silliness, a man driven to extremes of anger and frustration and reacting by doing something so pointless and stupid we can't help but laugh.
First, he reverses the car up onto the pavement. There is no real need for him to do this as there is plenty of room in the road to turn, but the fact that this is where he is when the car finally breaks down adds a tiny sliver of extra jeopardy to the situation.
This is just once example of something that is pervasive in this sequence, which is that Cleese is making loads of quite small choices each of which makes the scene funnier, and the combination of which make it hilarious. Taken individually they seem small but the layering up of them, tips the whole thing into something extremely funny.
For example, his reaction is immediately, funnily over the top, but from the way he shouts "oh god", to the way he calls the car a "vicious bastard" (far more specific and peculiar than the way we might normally personify inanimate objects) he constantly adding to your knowledge of the inner workings of his Fawlty's mind. The richness this creates makes it all the more satisfying.
He talks to the car like it is a person, but he also ups the ante on this throughout the sequence. The early "vicious bastard" implies that the car is a nasty spiteful thing that has actively malicious in intent. Then he counts to three, as you might with a child, to give the car a chance to acquiesce. What's great here is that when he reaches three, he doesn't try and start the car again – we don't hear the engine. His anger is so complete that he expects that car to start without him even doing anything. Like he is stepping back from the situation in disgust and expects the car to redress the balance by starting of its own accord. There is a sense of petty justice here, the kind of justice you can only apply to a person; the kind of justice that starts expecting recompense as well as acquiescence. This is a tiny detail, but again, we notice, and we find the whole thing more funny because of it.
Of course, this is more than just yelling at an object like it's a person - which would be funny in itself. There's a whole relationship here, a battle of wills implied by these language choices. The car hates Fawlty, the car is a child who's misbehaving, and the car needs to make up for this behaviour by starting on its own.
And now he's out of the car, hopping and bouncing in that trademark Fawlty style. Wagging a finger and reminding the car that he's warned it before about this, that he's "laid it on the line [...] time and time again". The car should know that what's coming is entirely its own fault. This is personification taken to such an extreme, that it would signify mental illness if it were life, but here it just serves as a further insight into the twisted logic of Fawlty's mind, the paranoia, the sense of injustice.
He's wearing formal evening wear, a black suit and a black bow tie. The contrast between his appearance and his actions is a wonderful concoction, and whilst what he's wearing is entirely believable in the context of the rest of the episode its effect on this sequence is undeniable. Again with the little details.
Then finally with the immortal words, "I'm going to give you a damn good thrashing", and he disappears from the frame.
He returns holding what can be best described as a-bit-of-a-tree. A branch, splayed at the end with leaves still attached. Not a stick, not even aerodynamic enough that he can do any real damage. The fanning of the leaves actively prevents the thing from being swung at any speed, so what we see is a man in a suit ineffectually swishing at his own car with a leafy branch. In our heads, we fill in the blanks: he went off looking for something to hit the car with, he couldn't find anything that would be effective, so he pulled this branch off a nearby tree.
There's a shock to this. Even after him mentioning the "damn good thrashing". Having seen the clip so many times now it's hard to remember, but I honestly wasn't sure what was going to happen. If he had returned with a proper stick and started smashing his car to pieces, it wouldn't have been as funny. If the way he moved had been less Basil Fawlty and more angry tough-guy, it might have been disturbing. But what we see perfectly undercuts the anger with ineffectual impotence, the anger is way, way over the top, but it is not to be feared. The violation is benign.
This, I think, is the key to this sequence and potentially the character of Basil Fawlty in general. Fawlty is a man of extremes; he constantly goes further, doing more than we would in his position. His unwillingness to give up on his ambitions, the maniacal way he attempts to wrestle control of situations, and finally, in this sequence, the way his anger erupts when the world does not conform to his needs. Through all of this, all these violations that would make such a character positively scary if we met them in real life, it is his impotence, his lack of effect, that makes him safe (and therefore funny).
It is interesting to think about how "being on TV" plays into this. That safety we get from the distance that TV brings. He's safely inside the box and therefore we can laugh knowing that despite his lack of control he can't harm us. How would it feel to watch this happening on the stage? The conventions of theatre should offer us the same safety but might the physical proximity might make the whole thing more disturbing?
I doubt these are considerations that John Cleese was thinking about when performing all this, but his knowledge and comedic instinct meant that he made all the right choices. The sequence is almost perfect because almost every part of it adds to the effect, there is no waste, nothing that doesn't have a purpose. The combination of them all together meant that my childhood self was powerless to resist it.