That's a nice way to look at it for oneself, but not a good strategy for filling it out for bosses.

All advice I've seen about self-evalution requests so far suggests that you should say zilch about failures and pile the praise on yourself wherever remotely possible. You were tasked with creating part of your own paper trail, and you don't want it to contain anything that could be used against you at later opportunities.

(This assumes a large corporate setting. I'm not sure why it would require a formal piece of dead tree to communicate about these things in a small shop with flat structures and good relations.)

Makeshifts last the longest.