I've taken the hard determinism pill and it's both liberating and bleak at the same time. If I really embrace it, it means no more of my neurotic downward spirals into second-guessing things like what I ate for breakfast one morning 20 years ago, because that decision was just a product of every event from the birth of the universe up until that moment. On, the other hand, it means that the future already exists, unknowable, and is hurtling toward me.
If I experience an external reward and say "I'm going to work hard from now on to get more of that," it doesn't mean that I decide to work hard from now on. It means that the reward and the sum of all events from my birth have caused a state in the present which I expect will cause me to continue to work hard. Although with hard determinism, there really is no causality, because there is no split timeline from which you can take out one event and observe the effect of its absence on future events.