Came across this post on Murphy's Law(s) on What ever you want, baby and after browsing thru the actual Murphy's Laws site, I concluded that the original postulation has taken a hell lot of variations since then ;p

For example,

"All the good ones are taken. If the person isn't taken, there's a reason."
(Food for thought; so maybe that's why the babe at the other table's by herself.)

"When the lights are out, all women are beautiful."
(Something that's damn true in dimly lit places like clubs as well, lol.)

Or this one ;p

"To err is human, but to really foul things up requires a computer."

These few are absolute classics though:

Murphy's Law of Thermodynamics
"Things get worse under pressure."

The Murphy Philosophy
"Smile . . . tomorrow will be worse."

"In nature, nothing is ever right. Therefore, if everything is going right ... something is wrong. "

Hilarious :)