Everyone knows Murphy's law... "Anything that can go wrong will go wrong." Well here are some similar laws...variations on the same theme:
Law of Mechanical Repair - After your hands become coated with grease, your nose will begin to itch and you'll have to pee.
Law of Gravity - Any tool, nut, bolt, screw, when dropped, will roll to the least accessible corner.
Law of Probability -The probability of being watched is directly proportional to the stupidity of your act
Law of Random Numbers - If you dial a wrong number, you never get a busy signal and someone always answers.
Law of variation - If you change lines (or traffic lanes), the one you were in will always move faster than the one you are in now (works every time).
Law of the Bath - When the body is fully immersed in water, the telephone rings.
Law of Close Encounters - The probability of meeting someone you know increases dramatically when you are with someone you don't want to be seen with.
Law of the evidence - When you try to prove to someone that a machine won't work, it will..
Law of Biomechanics - The severity of the itch is inversely proportional to the reach.
Law of the Theater or stadium - The people whose seats are furthest from the aisle, always arrive last. They are the ones who will leave their seats several times to go for food, beer, or the toilet and who leave early before the end of the performance or before the game is over. The folks in the aisle seats come early, never move once, have long gangly legs or big bellies, and stay to the bitter end of the performance. [The aisle people also are very surly folk too.]
Law of gym Lockers - If there are only two people in a locker room, they will have adjacent lockers.
Law of Logical Argument - Anything is possible if you don't know what you are talking about.
Law of Physical Appearance - If the clothes fit, they're ugly.
Law of Public Speaking - A closed mouth gathers no feet.
Law of seeing a Doctor - If you don't feel well, make an appointment to go to the doctor, by the time you get there you'll feel better. But don't make an appointment, and you'll stay sick.
Law of Interior decor - The likelihood of a slice of buttered toast landing butter-side-down is directly proportional to the square of the price of the carpet. [added by Bob Cleveland to the original list]
Which brought a smile to your face?