We are all familiar with Murphy's Law and its logical extensions (my favorite is "dont force it, get a bigger hammer,") so it is only natural that with research, I have compiled a list of applied murphyisms relating to photographers.

You are not Ansel Adams

Neither are you Herb Ritz

Automatic Cameras - Aren't

Auto Focus - won't

No photo assignment remains unchanged after the first day of shooting

If a photo shoot goes too smoothly, then the data will be corrupted

If it's stupid but it works, it isn't stupid

Success occurs when no one is looking, failure occurs when everyone is watching

The most critical memory card gets magnetized

Photo Assistants are essential, they give photographers someone to yell at

The one item (batteries, film, electrical outlets and etc.) you need is always in short supply

Interchangeable parts aren't

Weather never cooperates

Everything always works in your home, everything always fails on location

For every action, there is an equal and opposite criticism

The newest and least experienced photographer will usually win the Pulitzer

There is always a way, and it usually doesn't work

Things which must be shipped together as a set, aren't

No photojournalist is well dressed

No well dressed photographer is a photojournalist

Professional photographers are predictable; the world is full of dangerous amateurs

shots of children only happen at two times:
-when the kids are ready
-when you aren't ready

client Intelligence is a contradiction

There is no such thing as a perfect shoot

The important things are always simple

The simple things are always hard

Flashes will fail as soon as you need them

A clean (and dry) camera is a magnet for dust, mud and moisture

Photo experience is something you never get until just after you need it

The self-importance of a client is inversely proportional to his position in the hierarchy

The lens that falls is always the most expensive.

when you drop a lens cap, the inside part always lands face down in the mud.

Your batteries will always go dead or you will need to swap memory cards at the least opportune moment.

Lenses are attracted back to their source - hard rocks.
Corollary:
The more expensive the lens, the greater the attraction.

Safelights - aren't.

The greater a photographer's excitement, the greater its chance of fogging film, scratching prints, and deleting files.

The success of an assignment is inversely proportional to the product of its importance and the number of people watching.

Strobes only explode when lots of people are watching.
Corollary:
Strobes only work when there is nobody else to see.