Commentaries and Corollaries on Murphy's Law

Murphy: If anything can go wrong, it will.

Historic original sentence: "If there is any way to do it wrong, he'll find it."

Murphy's Mother's Law: My son was right.
The Murphy Philosophy: Smile . . . tomorrow will be worse. 
O'Toole's Commentary to Murphy's Law: Murphy was an optimist.

Anything that can go wrong, will go wrong. 
If nothing can go wrong, something will (at the most inopportune time).
Everything will go wrong at one time - that time is always when you least expect it.
Given the most inappropriate time for something to go wrong, that's when it will occur.
If the possibility exists of several things going wrong, the one that will go wrong is the one that will do the most damage.
If there are two or more ways to do something, and one of those ways can result in a catastrophe, then someone will do it.
If you perceive that there are four possible ways in which something can go wrong, and circumvent these, then a fifth way, unprepared for, will promptly develop. (It will be impossible to fix the fifth fault, without breaking the fix on one or more of the others.)
The probability of a given event is inversely proportional to it's desirability.
Left to themselves, things tend to go from bad to worse.
If everything seems to be going well, you have obviously overlooked something.
Nothing is as easy as it looks.

There's never time to do it right, but there's always time to do it over. 
Everything takes longer than you think. (Hofstadter's Law: It always takes longer than you expect, even when you take Hofstadter's Law into account.)

When a broken appliance is demonstrated for the repairman, it will work perfectly. 
All warranty and guarantee clauses become invalid upon payment of the final invoice.
If it jams - force it. If it breaks, it needed replacing anyway. If it doesn't fit, use a bigger hammer.
It works better if you plug it in.
When all else fails, read the instructions.

Murphy's Constant: Matter will be damaged in direct proportion to its value.
Murphy's Law of Thermodynamics: Things get worse under pressure. 
Preudhomme's Law of Window Cleaning: It's on the other side.

Never make anything simple and efficient when a way can be found to make it complex and wonderful.
A 900 dollar .... (name your component) will blow just in time to save a 10 cent fuse.
As soon as you make something idiot-proof, along comes another idiot.
Any wire cut to length will be too short.
In an instrument or device characterized by a number of plus-or-minus errors, the total error will be the sum of all the errors adding in the same direction.

The amount of expertise varies in inverse proportion to the number of statements understood by the general public.
In any given calculation, the fault will never be placed if more than one person is involved. (In any given discovery, the credit will never be properly placed if more than one person is involved.)
The man who can smile when things go wrong has thought of someone he can blame it on.
In any hierarchy, each individual rises to his own level of incompetence, and then remains there. 
Never argue with a fool, people might not know the difference. 
In case of doubt, make it sound convincing. When in doubt, mumble. When in trouble, delegate. 

Nature always sides with the hidden flaw. 
Mother Nature is a bitch. (The universe is not indifferent to intelligence, it is actively hostile to it.)
Nature always sides with the hidden flaw. ( The hidden flaw never stays hidden for long.)
When it rains, it pours.
You cannot successfully determine beforehand which side of the bread to butter.
If rats are experimented upon, they will develop cancer.

You will always find something in the last place you look. 
No matter how long or how hard you shop for an item, after you've bought it, it will be on sale somewhere cheaper. 
The other line always moves faster. 
Any small object when dropped will hide under a larger object.
No child throws up in the bathroom.
Anything good in life is either illegal, immoral or fattening. 

In order to get a loan, you must first prove you don't need it. 
A verbal contract isn't worth the paper it's printed on.
Paper is always strongest at the perforations.

With extremely few exceptions, nothing is worth the trouble.
It is bad luck to be superstitious.
The chance of forgetting something is directly proportional

credit: from the net and from Freie Universität Berlin, Institut für Chemie