coincidences.

I personally don't believe in coincidences. I think everything and everyone comes in and out of our lives at certain times for a reason, whether or not we're aware of that reason at first.
I don't think this affects free will at all, though. I believe that what we do with these influences are entirely to our discretion. but everyone who you pass, everyone who you talk to, and everything you see, it's all there for some reason.
Even things that seem bad. Things seem simple and straight forward on the surface, but think about all these strange "coincidences" that have affected people you know.
I was told once of a man who was always late to everything. His wife said he'd be late to his own funeral. On September 11th he was late to work, and missed the train. He wasn't in the World Trade Towers when they came down.
Eerie coincidence, or something bigger.
During a heavy snowstorm in New York City, a tree came down in Central Park killing a man in his 50s. Tragic, absolutely. But at that exact moment, that man was standing in the exact right place for that tree to come down on him and take his life.

That brings me to another theory of mine. Whenever it's your time, it's your time. If it's not your time, you'll avoid death, even very narrowly sometimes.

When we're born we're stamped with an amount of time. We can't see it or know how long it runs for. It's only revealed to us when it runs out.

So don't lock yourself in your house fearing all outside causes of death. If it's your turn to check out, your carbon monoxide detector might not have been hooked up right, after all.