Yeah, this sounds like too _little_ stress to me. Imagine a bell curve with stress on the X axis and performance on the Y axis, and there's a sweet spot in the middle where you're getting enough of a kick to motivate you, but not so much that you're drowning.
Yes. And I've personally found that the "sweet spot" in the middle is all too elusive.
In my career I think I've spent the majority of time at one extreme or the other. Feast or famine: overworked & stressed or underworked & depressed. When you can hit it just right in the middle, life is truly great. But rarely have I been able to sustain it for more than a couple months at a time. Let me know if you've found the secret :)