The word "wahala" Is used by Africans to refer to "problems". "No wahala" means "No problem". There are several times individuals have involved themselves in wahala, sometimes it starts as something small hoping it would go as expected but escalates to something big, probably a fight that cannot be stopped easily.
This could be a case of a police officer who stopped a car, opened the door, entered and shut it without knowing whose car it is, only to find out the occupants of the car are ritualist and there's no way he could go out or a man who slaps a military official on mufti only to realize he's a soldier . Most times we say "wahala no dey finish" meaning "problem doesn't have an end" we keep getting into one problem or another no matter how careful we seem to be.
A scientist in a lab had mixed several chemicals which was intended as an experiment to turn humans into apes. When he was done with the mixture, he placed the conical glass containing the mixture on the top of a bookshelf. He was about to go out to get a cremated body to verify if his mixture could give him the result he had expected when he realized he remembered he had forgotten a book on the shelf. He was trying to get the book when the unbalanced shelf fell, the conical glass slip and broke pouring half of the mix chemical on him. He was afraid he could be transformed to an animal, quickly, he ran to his lab, mixed a different chemical hoping to neutralize the effect of the chemical which has poured on him, only to be the actual chemical that transformed him to an Ape. Wahala! He screamed. That which he feared, came knocking at his doorstep.
Wahala happens in our day to day life, and it comes from little things that we least expect. Someone says as long as we are alive, wahala will surely come, it's a natural event that we can't run away from.