Ah, the quest for the
mot juste.
There's nothing inherently wrong about your mindset. It all depends on what you're looking to get out of your writing.
However, if you really want to tame your inner editor, you should try
NaNoWriMo next November, if you aren't already doing it. Its philosophy is "the good is the enemy of the fast", and that sounds like a good change of pace for you. Quite a few Mizaharians are NaNoers, myself included, and we encourage people to write Miza-based novels should they feel like it (they can also get canonized if they respect our lore).
I've learned to just ride the writing through the rough parts. I am guilty of horrible repetitions and a few weird-sounding sentences, but then again I write more for the story than for the stylistic exercise. Moving the story forward is my reward, and I can make sacrifices to that end. Needless to say, your mileage may vary, but you might want to consider what you consider to be rewarding about the act of writing and focus your mind on reaching that state when you write.