I consider myself senior, but I haven't really lost my optimism. I don't think becoming a senior should mean losing optimism. For me it's the opposite. I have much better understanding how to achieve something than before so I have the confidence that I can definitely do it. Maybe it's my personality though, that instead of thinking what the obstacles are, I think how I'm going to visualize and build it.
But I can see how it's different from plenty of other folks, and I think it comes down to personality. Usually I don't or can't think of challenges/weaknesses up front and I like to just dive in. I have been criticized and given feedback of having this flaw, but I have unrelenting belief, that I can solve everything on the fly and for me it has worked in the past.
It's like my mind is unable to bother or concentrate on what the obstacles will be. And it's frustrating because many people expect you to come up with a plan and potential obstacles beforehand while my mind just wants to jump in.
Most advice tells you to think/ask questions/plan before you code, but I code while thinking and iterate on that code. I can't think or concentrate if I'm not coding or actively solving the problem. If I try to plan something, it's half-assed and to me it seems useless and it kind of pretends to be a viable plan and when I finally do it, I do it completely different from the plan anyhow.
Not saying it's the right way, but maybe it's some sort of thing similar to ADHD where I just can't focus without building. And I am very impatient as well so if there's something that needs to be built or solved I will need to jump on it asap and get it solved asap. If I'm not building and am planning I have this increasing anxiety, that I should just be doing it.