I think it's one of those things that starts to boil down to a chicken-and-egg question. You get trapped by the words... 'free will', the phrase itself seeks the 'will' as a sort of First Cause of personal actions. We decide our own course of actions. But of course, our own decisions are to a large extent predetermined results of our own personalities, which are in turn products of our birth, upbringing, and on and on... so are your decisions really 'decisions', or simply a predictable and inescapable result of your psychological makeup and the mental and emotional calculation your brain makes in evaluating a situation and appropriate course of action?
One need look no further than certain forums to see the reliable predictability of individual personalities.

Is 'free will' an illusion when we're really just slaves to cause-and-effect? Of course, quantum uncertainty relieves some of the predictability, but randomness and 'will' are not the same things. Then what does it really mean to 'decide' something anyway?