It's an interesting roleplaying challenge to play a character with serious regrets about their past actions.

The good thing is that, depending on the game, you might be able to acquire some method of going back in time to fix it! Try that for a character/adventure hook some time.

Transcript

Palpatine: Traitor!
[SFX]: krzzrkzkzzz... {Palpatine hits Mace Windu with Force Drain}
Mace Windu: Oh my god! I remember everything now!
Mace Windu: I've been controlled... altered... implanted...
[SFX]: Krzzrkzzz...
Mace Windu: Nute Gunray is behind everything...
Mace Windu: The Jedi Archives, the clone army, my apartment block...
[SFX]: Krzzrkzkzzz...
Mace Windu: I've been played for a fool...
[SFX]: Kzrzzzz...
{Mace Windu is flung out of the window by the Force Drain and falls}
[SFX]: Kzzrkzz... ...zkzz... ...zzzt
Mace Windu: Tell the Jedi Council... {fainter} I'm sorry... {very faint} for my failure...
Palpatine: Oh dear; I... may have made a terrible mistake.
Anakin: No, don't you see? They're all in on it! The whole Jedi Council.
Palpatine: He just apologised.
Anakin: For failing to kill you.
R2-D2: Yeah, I'm often sorry I haven't killed Obi-Wan.