I kinda see what your getting at. But i was thinking that maybe we can do what we want like decide to steal cereal out of the back of a semi-truck (personal example). But maybe that pisses off the truck driver who then gets mad and distracted and because of this gets into a car accident. So what im saying is that what your saying in general could be true, but i dont think that chewing on your fingure effects everything in the univers.
There is a flaw in what i just said though cause maybe there was a chain of events through childhood or even just something that could of influenced me that day which made me decide to jack some cereal. So maybe some things we decide and some are decided for us but i dont think that its possible to ever find this out so you just gotta go with it and hope for the best.
I thought of a good example too, its from a movie i saw called 'pie' the math sign not the word. And in the movie he pours some cream into a cup of coffee and it spirals all over and makes a trippy looking swirls of random-ness. In those swirls there was the initial pour into the cup that gets it going and from there on defects in the coffee or cream pushing other cream and so on just keeps it going in defferent directions till it gets to the point where it stops moving. Maybe life is just a big version of this and there was the initial BANG (big bang) and it was so huge that were still twirling around and going out of control.
Just my thoughts on the matter