Dear Cityboy, what outfit can I get away with on dress-down Friday?

Dress-down Friday is a hideous minefield that instils icy fear into the heart of every right-thinking banker. Like all American exports (e.g. grey squirrels, peanut butter and ‘jelly’ sandwiches, the 12-inch Weiner) it should be treated with deep suspicion.

The principal danger is that you receive a last-minute demand to participate in some vital corporate finance meeting; you invariably turn up looking like some hipster from Dalston… and no-one wants to do business with a hipster from Dalston.

As a general rule it is never wise for bankers to put their heads above the parapet. For example, to recommend stocks that no-one else likes, rather than just mindlessly following the crowd, will invariably result in you becoming a laughing stock, while making the same mistakes as every other dingbat stockbroker out there means you can never be held accountable.

The same principal applies when choosing what to wear on ‘casual Friday’ and the accepted uniform is simple: khaki chinos, brown leather Oxfords, a yellow Polo shirt (summer) or checked Thomas Pink shirt (winter) with a navy blue single-breasted jacket. ANY deviation from this outfit will suggest to your boss that you are an unreliable weirdo.

Dear Cityboy, what should I do if get a zero bonus this year?

A zero bonus, or ‘doughnut’, is your firm’s less-than-subtle way of telling you that you are surplus to requirements. Their profound hope is that you will have the good grace to simply crawl under a rock and die. It is therefore a form of constructive dismissal and is obviously a favoured option for banks because it’s a hell of a lot less expensive or potentially litigious than sacking you.

I’m afraid the only option you have when effectively being told to sling your hook is to do just that. If your firm has got away with giving you nothing one year and you stick around they will know they can away with it again next year. A deluded sucker at my old firm received three doughnuts in a row and accepted this ignominy because he genuinely believed his boss’s piss-poor excuses about Russian bonds defaulting.

A zero bonus, or ‘doughnut’, is your firm’s less-than-subtle way of telling you that you are surplus to requirements.

These clueless dingbats are invariably regarded as ‘the walking dead’ and will soon discover that colleagues avoid them like the plague, fearing that their failure is contagious. The only way out of this horrific situation is to try to find a new job at a firm that hasn’t heard about your degrading humiliation: you take your brave pills, hold your head up high and march into the interview room praying to God that none of the pinheads inside know the awful truth.

Dear Cityboy, why do bubbles happen?

Bubbles have happened throughout history, whether its tulip bulbs selling for thousands of pounds in 17th-century Holland or cocky dickheads like me buying worthless shares in unprofitable internet companies (that will ‘revolutionise stamp collecting’ or some such crap) in early 2000.

Asset price bubbles occur because investors generally suffer from a herd mentality and are prone to ‘irrational exuberance’ when prices seem to be on a non-stop journey upwards.

Mass hysteria can grip crowds and markets alike, especially when rising prices and increasing confidence form what I call ‘the virtuous circle of bullshit’.

What makes the party really take off is when ‘capitulation’ occurs. This happens when the ‘bears’ get so tired of being perpetually wrong that they pile into the market. When the fund manager PDFM sacked its bearish chief investment officer Tony Dye (aka ‘Dr Doom’) in March 2000 we should all have known it was time to crystallise our phantom gains. That would have certainly prevented me crying into my cornflakes two years later when I realised that my TMT portfolio, after dealing costs, could buy me two packs of Smarties.

Of course, you know you’re at the real peak of a stock market bubble when taxi drivers begin giving you share tips.

Do you have any questions for Professor Cityboy? Email them to letters@squaremile.com. Follow Cityboy on Twitter at @cityboylondon