How to Beat Discouragement

I'll admit, sometimes I feel like I never finish anything I start. But that feeling is a total lie—I've finished novels and short stories, written and produced several songs, finished multiple video projects—but yet that feeling can crush my motivation. And having connected with other writers, artists, and dreamers in the past, I know this feeling poisons many of us.

Why do we feel this way even when it's not true?