London can turn even the most mild-mannered pedestrian into a frothing psychopath. This heaving metropolis bombards the senses so much, one might well consider charging it with grievous bodily harm.
'Watch where you tread' is good advice for the uninitiated. Far from being paved with gold, as legend has it, the streets are strewn with rubbish of all descriptions, from burger boxes to hypodermic needles. Eighty tonnes of litter are removed from the streets of Westminster1 alone every day. To be fair, not all of this is due to thoughtless litter-bugs - litter bins are a rarity in the city centre2.
Spitting, perhaps encouraged by football players who constantly gob during televised games, leads to an interesting hop, skip and jump effect as one tries to miss great blobs of mucus dotted among the chewing gum and dog waste.
Beggars congregate in London from across Britain and as far afield as Eastern Europe. In scenes reminiscent of Victorian times, women in rag-like clothes will be hunched up against a wall, babies in their arms, begging for charity3. They receive contemptuous glances from passers-by, many of whom are outraged that these mothers should subject their children to the pollution, noise and cold for hours on end. The police can do little but ask them to move on. When they do move, it is often to the relative warmth of the Underground, where they walk the carriage aisles with little cards, on which a scrawled message in bad English pleads for money.
Beware the organised gangs of charity collectors and market researchers, another obstacle for those trying to get from A to B. Many of the latter are paid an hourly rate comparable with nurses and teachers. They line up on both sides of the pavement and, with a cheery smile, thrust clipboards in your ribs while asking if you can spare a moment. Unless you want to appear unfashionably time-rich, or a lonely sad-case who has no one else to speak to, the best answer is, 'Sorry, no'.
There are also visitors who stop in the middle of the pavement to gossip or check their street atlas like shell-shocked provincials. Of course it never occurs to them they impede the feverish flow of humanity around them. The masters of pavement-blocking are teenagers with backpacks the size of a fridge/freezer, who congregate in and around Oxford Circus tube station for the evening rush hour, like the swallows arriving at Capistrano.
One of the greatest threats to pavement peace is the argument about which side to walk on. In London, it is a centuries old custom to walk on the right side, so that the left hands of approaching persons pass each other. This is alright for those from right-hand drive nations, where they also tend to walk on the right, but for Australasians and others from nations where the keep-left rule applies - and even Britons from outside the city - it can get rather confusing.
Brave souls can avoid the crush and confusion altogether by stepping off into the gutter. Aside from the possibility of being hit by those crazy enough to drive in this city, or a lycra-clad loony on two wheels4, this is generally a successful if somewhat pants-wetting way of keeping pavement rage at bay. Oxford Street is a prime spot for watching gutter walkers, and you may pick up tips on technique.
People who aren't quite brave enough to risk their limbs in the gutter and are of a reasonably slim physique can try walking on the narrow strip of pavement between the lamp posts and bus shelters and the kerb.
Assuming you have fought your way successfully through those who usually stand around outside Underground entrances blocking them, you must then remember to keep left rather than right once inside - except on the escalators, of course.
Those who grow tired of London are not tired of life, they are merely exhausted from trying to maintain their sanity on the streets.