Disaster dont call me an idiot but.....

Good PSUs kick off in the event of a short? -So I'm the god of computer fires because of my cheap PSUs?
(no... It still doesn't explain the ones that lit up when I got close to them...)

 

I have actually seen it recommended somewhere to keep it plugged in to drain static away. I can't remember where though...

The worst I have done is plugging in my CD drive while everything was on - it didn't stay on though! lots of lovely sparks and a bang, but everything still works

 

When I did this, my DVD-Burner died

 

lol

 

By all means keep the AC cord plugged in to allow a good path to earth for static discharge but don't have it switched on.
Anybody that starts swapping pc bits whilst the pc is still powered up is asking for trouble and if you've managed to do so without damage to either the mb or the bit you're yanking out then you are riding your luck in my opinion. But hey mabye some folks just don't care and can afford to fry various pc components and simply splurge out cash on new ones, whereas some live on a tight budget and can't be quite so casual about trashing expensive kit.

 

worst one is laptops which suspend instead of turn off and you don't even rearlise! I lost some ram due to that I felt very stupid :|

 

Well, that's not the problem. The problems starts when the power lines are unplugged before the signal lines. In some cases this will make the signal lines feed the power to the unit. The signal lines, however, aren't designed to handle no way near the currents the power lines do.

all PSUs shut down when they are shorted. The currents still have time to kill stuff.

You want the ground wire (earth) connected to discharge static electricity. It should be connected via a large resistor (10Mohm i think), though. If it's directly connected it could potentialy get dangerous for both you and the parts inside. When the computer is in use there should be no resistor!

This is why you always should take out the battery when working with laptops... Shorting out batteries could actually be way worse than shorting a PSU. Batteries doesn't shut down, you know. (The internal fuse takes quite a bit of current and time to burn of)

 

Looks like the computer gods are on your side