A butterfly effect is the phenomeon that a small change in initial conditions that leads to a significantly different result than if the initial conditions haven’t been changed. Have you personally witnessed such phenomeon?
Example: Your pet seeks attention and you decided to spend a few seconds to pet your pet before leaving for work/a party/shopping for grocerries/etc. You drive to an intersection and the light turns red just a few seconds before you arrive, the car ahead of you passed the intersection sucessfully. When you eventually arrive at the next intersection, you find the car ahead of you was hit on the side by another car from the intersecting road. The driver in the car ahead of you was instantly killed.
You’ve just been saved by your pet.
I was in line to buy tickets to a concert. The tickets didn’t cost much, but I was poor, so as I was in line I was wavering back and forth between the cheapest tickets and the second cheapest. When I got to the front I was on the side of the cheapest.
Another person who bought the cheapest was an incredibly cute girl who I met there and ended up dating for several months, and that relationship, after it ended, gave me the confidence to make a move on another girl who I had long been attracted to, and our relationship made me choose the particular job that I chose because it let me move near where she lived.
So if I had been a couple of spaces further back in line, I probably wouldn’t have lived in that state for two years. True story.