Murphy's Law of Staff-Availability
"If you have to request assistance/advice from a store/office-employee, you will be obliged to wander all over da place and "search till Doomsday" to find someone who is not presently too occupied to listen to you. Yet once you finally receive your answer, THEN there will be ABSOLUTE MULTITUDES OF PERSONNEL just lounging around and making themselves available, and so you will feel like a total JACKA** for not having simply waited a few more minutes to ask your question, rather than wearing out your feet and legs from running all over da shop to find someone to ask!"
I spent over five minutes scampering up and down the aisles at Wally-World trying to find a "free" employee to ask about the availability of a certain product, but then afterwards, there were several non-busy staffpeople whom I met en-route back to my shopping-cart whom I could have asked just as easily at that point --- talk about a classic case of Murphy's Law of Staff-Availability! :P :P