h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Don't go via Heathrow if you can possibly avoid it. When they say they want you to check in 2 hours before take-off they mean it.In order to get a cheap ticket I have used it three times in the last 2 years.
The first time the fire alarm went off three times while I was trying to check in, thus reshuffling the queue.
The second time it actually took 1 hour and fifty seven minutes from joining the queue until someone trawled it "Is anyone else trying to get the plane to Hong Kong? please come to the front of the queue." No time for any "duty free" there then
Last month the conveyor belt from where your luggage is weighed was broken. So the ground staff were working to rule and refusing to pick it up. They were also in a uniformly foul temper and refused to take any requests for seat position "You should have been here earlier" (I was actually in the queue when it opened albeit not the first person) or allow a carrier bag in addition to hand baggage "Can't you read. One piece of hand luggage only"
Since it takes hours to get to my home in North Lincs I'm giving this up for a game of soldiers and reverting to the more expensive alternative - go to Amsterdam and then fly across to Humberside. This also cuts out the dreaded M25.

The only time I have been in Heathrow was when I went to Saudi Arabia, land of no alcohol. So of course I spent a good couple of hours staring at the SALE! Dirt cheap whisky! signs. The plane was even delayed to make it worse! I'll bet they planned it.

If like me you can't avoid Heathrow (Heck, I live next door to the place) here are some points for there:
Heathrow, being huge, is split into 4 terminals (with a 5th on the way)
Terminals 1, 2, and 3 are very close to each other, but 4 is on the other side of the airport. Allow extra time to get from one to the other and make sure you know which one you are using.
In the past you took a bus that circled the airport (a pleasant trip as it takes you past the mind-bogglingly huge sheds they park the jumbos in) but these days you are encouraged to use the heathrow express, a fast expensive train into london. It stops at T3-ish and T4, so you can use it for free to transfer. The journey takes only 5 mins, but bear in mind that the trains are located what feels like several miles below the surface of the earth, so again allow plenty of time.
If you are travelling on from Heathrow, you can use the aforementioned heathrow express to get into Padington station in about 15 minutes for £15. If you're cheap, take the regular underground; 45 minutes but £4. T1 is next to the Heathrow bus station, from whence coaches depart for virtually anywhere in the UK. (An advantage of living close to the airport is that you can easily get such coaches to anywhere you want to go). Also near the bus station is the chapel should you need a quiet moment to escape from all these confusions. It's a little hard to find; basically look for the air-traffic control building (easy to spot - lots of doors saying "it is illegal to go thru this door") and circle it until you find the chapel.
If you are going somewhere local do try the local buses; the local black cabs are expecting big fares (£50!) into central london and so tend to squirm if you want to go somewhere less expensive.
If you have a lot of time to spare at Heathrow between planes go to T2, go outside and round the side; you will find a lot of stairs up to the roof where there is a small cafe and various views of the airport, the planes, and most interesting of all, the plane-spotters.

I'm sorry, you don't tempt me.
Instead of the nice bus, they now want you to go through not yet completed tunnels (not on my own, I'm not)
It is almost impossible to find out which terminal you're supposed to be going from- unless it's the first bit of your return ticket when a UK travel agent will be helpful
It's too crowded, whichever terminal you're using. The ceilings are too low. So it feels oppressive. The loos are dirty and the coffee (if you get time to drink one with their ludicrous queueing set-up) is filthy

On my trip home last summer I _did_ try to get home to Lincoln by long distance bus. It was one of the hottest days of the year, we got stuck on the M1 and I was sent miles out of my way [necessitating a two hour wait in Nottingham] because the booking clerk had never heard of Lincoln. I got to Heathrow at 5am and to Lincoln at 7pm. This is not an experience I'd recommend to anyone after a night flight from Hong Kong (Oh, and British Airways is not MY favourite airline either, but that's another rant)

Oh, Heathrow

*waits until blood pressure has come down to safe levels again*
*restarts modem which has switched itself out due to no use for ages*

I once spent close to an hour there, looking at an empty, unmoving carousel that was supposed to bring me my luggage in time for my connecting shuttle to Glasgow (then, you still had to customs clear your luggage upon setting foot in the UK).

OK, that happens in every airport, agreed. But very few of them have the audacity to put a HUGE poster above the carousel saying "London Heathrow. The world's most successful airport".....

And they also did ask me why I only checked in at the last minute (thanks to higher powers that I *had* listened to the advice about leaving LOTS of time between connecting flights).