Every character needs a turning point. A fateful decision. A moment that defines the rest of their life.

Often this occurs without much fanfare. It could be a decision made in the heat of battle, amidst the whirls of blades and the roll of dice. Or something that occurs in a conversation with the king, that changes the course of empires because the GM has decided that the king's reaction will be based on what the PC does. You can set up situations like this.

But an interesting way to to approach them instead is to draw attention to them. Make it abundantly clear to the character (and the player) that this one decision will have the potential to change everything about the campaign from now on. Lead them by the hand. Say, "These are your choices." Explain what a decision either way will mean, and how it will flow on to affect things across the span of continents, worlds, and decades.

Then sit back and watch.

Transcript

Obi-Wan: Listen to me. Your life is a lie.
Adam: Er, sure. Look, it's been real nice talking to you, crazy old guy.
Adam: I've got to go home. It's late, I'm in for it as it is.
{Obi-Wan retrieves something from a chest}
Obi-Wan: Your father's laser sword. This is the weapon of a Jedi Knight. Not as clumsy or as random as a blaster.
Adam: My father would die before he'd let you get your hands on any of his weapons.
Obi-Wan: You never knew your father.
Adam: What are you talking about?
Obi-Wan: This is your last chance. After this, there is no turning back.
Obi-Wan: You take the hovercar back to your moisture farm - the story ends, you melt down the droids and believe whatever you want to believe.
Obi-Wan: You take this laser sword - you stay with me and I show you who you really are.
{beat}
{beat}
{Adam takes the sword}
Adam: This has gotta be better than binoculars.