Shamelessly edited from an email I got today:
How do you know that you have been in London too long?

You say "the City" and expect everyone to know which one.
I thought everyone said that about the place they live in.

You have never been to The Tower or Madame Tussauds but you love Brighton.
True that. Brighton is an ode to blue-rinsed old ladies, cream teas and poodles during the day, and the queer/fetish community at night. How could I not love it?
Although, I have been to the Tower. When I was still a tourist.

You can get into a four-hour argument about how to get from Shepherds Bush to Elephant & Castle at 3:30 on the Friday before a long weekend, but can't find Dorset on a map.
Guilty.

Hookers and the homeless are invisible.
I can never seem to see hookers, so it must be true. Or maybe I'm just naive. Everyone round the age of 14 looks like a hooker these days.

You step over people who collapse on the Tube.
It depends on how bad they smell.

You believe that being able to swear at people in their own language makes you multilingual.
Hey, I might have been in London too long, but English I am not.

You've considered stabbing some one.
Oh yes. Yes, yes, yes.

You consider eye contact an act of overt aggression.

em>You call an 8' x 10' plot of patchy grass a garden.
I have a genuine park.

You consider Essex the "countryside" and you think Hyde Park is "nature"..
Isn't it?

You're paying £1,200 a month for a studio the size of a walk-in wardrobe and you think it's a "bargain".

You pay 3 pounds without blinking for a beer that cost the bar 28p.
I blink ,but soon after blinking I drink, and then I forget.

The UK west of Heathrow is still theoretical to you.
Well that's where the line stops, and so do I. Although, I went to Cornwall once.

You're suspicious of strangers who are actually nice to you.

Your idea of personal space is no one actually physically standing on you.

£50 worth of groceries fit in one plastic bag.
A tiny plastic bag.

You have a minimum of five "worst cab ride ever" stories.
Only minicabs, I can't afford black cabs.

You've mentally blocked out all thoughts of the city's air/water quality and what it's doing to your insides.

When the news that someone has thrown himself under a tube train it's just someone trying to delay your journey.
Got me there.