Perhaps I have too much trauma from past learnings. Like, childhood learnings, before I started self-guided studies at 18. Often enough I run into a list of things I don't know, and I become afraid. Then I recollect myself and procrastinate before finally getting to the study. The study is usually easier than anticipated.
But this is a bit of an oversimplification. Based on my biased view of my own track record, my normal acceptance for stress is something like "75% of the time unsuccessful, with accompanying hormonal and neural responses", and "25% successful, ditto". Which is to say, I spend most of my life depressed, and make up for it more than adequately otherwise.
Then I reflect on the sort of people I think are foolish, who seem to spend the majority of their time talking about success, but then have these minority periods of time when they are depressed. But after all, the averages are equivalent, I suppose. So it is just a preference about how one wishes to spend time.