I keep thinking about R5-D4.
He was all set for the big adventure, when out of the blue: poof. Bad motivator. Left behind.
A tragedy, but I bet it didn't even bother him that much at the time. After all, astromech droids are optimists by nature, and each of us is the hero of our own story. R5-D4 probably thought "Just a setback. No worries. This is only the beginning. Another opportunity will come along soon."
How could he have known that those fleeting few moments, during which he was the chosen one, were actually the peak of his role in the big adventure?
I bet he's still out there in the desert, wondering what the hell happened.
He probably thinks his best days are still ahead. Maybe he's right.
For all we know, he could be in great condition now.
Motivator repaired, fully operational. Ready to serve.
May the force be with him.