But you do; things occur as result of your deliberations and choices that wouldn't occur if you didn't exist. It's just that your deliberations and choices are the result of prior events you're largely unaware of.
You evaluate the options, weigh up the consequences, and make your choices. Subjectively they're free choices - you don't know what the outcome will be until you've decided it; objectively, they're the inevitable result of your genetics, development, life experiences, and state of mind at the time (also a result of all that stuff). The importance or weighting you give to various aspects of your deliberations depend on your mood, physiological state, what's on your mind at the time, your beliefs, your preferences, etc. - all themselves dependent on prior events.
You are a unique person, genetically, developmentally, and experientially... if the outcomes of those deliberations were not the result of all those factors, they wouldn't be your choices, would they?
And if we were to allow for some random 'noise' in all of that, the results would be proportionally less your choices, wouldn't they?