Tapestry

It's a Wonderful Life, in SPACE!

Picard's artificial heart fails and he comes to in a blindingly white space to meet Q, who gives him the score: "You're dead, this is the afterlife, and I'm God." They argue the point a bit, Q insisting he intends to give Picard a chance to make peace with his regrets. Picard admits to some regrets from his youth–including the altercation with the Nausicaan which left him with the artificial heart.

Q sends Picard back to his past, so that he can change things, if he wishes, and even promises to restore Picard to the 'present' with a real heart if he avoids getting stabbed. Picard plays things safe and does avoid the fight, but destroys his friendships in so doing. When he finds himself back in the present, he discovers that he is only a lieutenant junior grade; without taking risks, he was never able to advance in his career.

Declaring that he would rather die as he was than live an unfulfilling life, he asks Q to send him back, so he can set wrong what once went right. Q does, and so Picard does, and back in the present Picard has been saved from his injury. Was it all a dream?