When I was in philosophy class in high school, I was assigned the Determinism side of the Free Will vs Determinism argument, and argued it well enough to get some of my classmates really upset. I'm a big believer in Free Will, but there are small things that happen in our lives that can radically alter the trajectory of our lives, and it really makes me wonder. Let me give you three examples of insignificant things that happened in my life, my father's life and his father's life, without which I certainly wouldn't be who I am today, as I likely wouldn't exist.
Let's start with the squeaky hinge in the hospital room of my mother's grandmother. She was in the hospital for a check up and the squeak was really annoying. My father's mother worked in the hospital, and her father owned a hardware store, so she knew how to fix things like squeaky hinges. Now it happens that at the time, she was looking for a place to stay. She got to talking with my mother's grandmother, who it also happened had a room for rent in her house. You see where this is going.
My mother's father played the cello, sometimes with my father's father. My father's mother and my mother's father I believe had started some sort of relationship when he went off to America, as part of the all-Germans-aren't-so-bad tour following WWI, where he met my mother's mother and got engaged. They came back for a visit, and clearly the relationship with my father's mother was going nowhere, but my father's father's first wife had recently left him with two kids, and my father's mother decided to marry my father's father instead.
My dad is the 7th of 8 kids, and at some point was on a train with his father when they passed Hamburg. It was the middle of the night, when my dad should have been asleep, but he and his father were both awake as they passed a factory outside of town. My grandfather told my dad that the factory belonged to Uncle Otto, my mother's uncle, and my dad filed this away. A number of years later, my dad finds himself in Hamburg, having decided not to go back to East Germany. He's got no job, and no place to live, but he remembers Otto and his factory. He goes to the factory looking for Otto, but Otto isn't there. The foreman decides to have pity on him and gives my dad Otto's home address. He goes there, but Otto isn't home. His wife, however, is charmed and says he should stay for dinner, which he does, and shortly thereafter is working in Otto's tire factory.
At some point, Otto's niece Matilda comes to town, and Otto asks my dad to show her around. He does this, and is smitten. They get engaged some time after this and he comes to America, sponsored by Otto's brother (my mother's father, who went to America all those years ago).
As for me, I owe my marriage and current life to a quarter. My sweetie and I met in a production of Much Ado About Nothing (she was Hero, I was Claudio; it was like Romeo and Juliet, but flakier and without the death), for which she would not have auditioned if the quarter to decide between auditioning and going to Fiddler on the Roof had come down the other way.
So, don't sweat the small things. Just know that you never know which one will send you down the rabbit hole. (and I mean that in a good way, sweetie :)