The systems we set discourage us from revising our work and improving.
They also draw a hard line between creation and revision.

You write a paper, hand it in, done. Maybe you revise it. (For extra credit).

If you revise it, you probably already have that next assignment hanging over you.
So revision becomes secondary, unimportant, rushed. It's a nuisance.

You rarely do anything beyond typos, punctuation, and shuffling a few words around.
You probably never rewrite it from top to bottom.

Having to revise makes you feel worse about yourself.

Why couldn't I get it right the first time?

We try to predict things based on assumptions. 
When things don't go as anticipated, we blame ourselves for not guessing accurately enough. 

We feel disappointed that we now have to fix what we thought was done. 

We also separate our work into distinct stages. 
Design -> development -> testing. 

And when a bug is discovered during testing, it has to be "sent back". The beautiful flow is disrupted.

We try to make sure it doesn't happen the next time. 
We fail to realize it's a part of the process.
 
The only negative thing about this part of the process is what we call it, how we perceive it, and how we treat it.

-- 
It's not developing and fixing.
It's not writing and revising.

It's all one.