It's important to celebrate big achievements in a character's life. Weddings, major birthdays, graduations. Becoming the major villain in the story.

Organise a cake. Both in-game and in real life. If you're lucky the real cake might even be as nice as the in-game one.

Transcript

Obi-Wan: You've followed the full path, don't you see?
Obi-Wan: Do you remember? Humility leads to injustice!
{flashback to Anakin facing the defeated Count Dookû}
Anakin: Tell me now or I'll kill you!
Palpatine: No, Anakin; he must be brought to justice and tried for his crimes.
Anakin: The wicked do not deserve to live.
{flashback to Anakin rescuing Palpatine from General Grievous's cyborgs}
Obi-Wan: {narrating} Injustice leads to heroism.
Palpatine: Thank you, Anakin; I thought I may have breathed my last.
Anakin: Not while I'm around.
{flashback to Anakin talking to Palpatine in his office}
Obi-Wan: {narrating} Heroism leads to pride...
Anakin: I'm proud to serve the Republic, Chancellor.
{flashback to Anakin talking to Palpatine in his office}
Obi-Wan: {narrating} ... leads to patriotism...
Anakin: I want to serve the Republic as best I can, but I need your help.
{flashback to Anakin talking to Palpatine in his office after Mace Windu's death}
Obi-Wan: {narrating} ... to totalitarianism...
Anakin: I believe you are still a great leader. The clones will be loyal to you. Your decisive action will save billions of innocents.
Palpatine: We... must use the Clone Army to defeat the Trade Federation.
{flashback to Anakin's parting conversation with Padmé}
Obi-Wan: {narrating} ... to power...
Padmé & Anakin: "I made it all up..."
Padmé & Anakin: "to turn Palpatine against the Jedi..."
Padmé & Anakin: "and now I'm all-powerful."
{flashback to Obi-Wan interrupting Anakin choking Padmé with the Force}
Obi-Wan: {narrating} ... and finally suffering.
Obi-Wan: You're killing your own wife!
Anakin: What have I become?
{end flashback}
Obi-Wan: Your journey to the Dark Side is now complete!
R2-D2: Achievement unlocked!