Reflecting back on my own development as a writer and artist and looking at other people, I've noticed a lot of people's first idea for a project is a BIG one. Or at least the idea they really wanna do is overly ambitious.
Like a few years ago, if you would've asked me, I would've told you that I have this big long story that was gonna be my first comic and it was gonna be incredible. Like we're talking epic fantasy, a million different characters and locations, so many arcs and seasons 
And it sounds so stupid to me now, but I genuinely believed that. And yet, at that time I was stumped when I would have to even write a basic outline but I just told myself "I will write and draw it when I'm ready." And to be fair, that is what I'm doing now, but I'm putting in the work and learning through my current comic rather than waiting around. That big project has been scaled down and I've started properly outlining it for the future, and I can actually write well now because of working on my current project so yipee!
But like, I've seen so many people with the same thing- big, grand ideas and seasons and no idea how to execute it. And I completely understand it because you can look at works that inspire you and go "I want to do something that amazing!" I was originally stuck in the mindset that that big story was the only thing I was ever gonna make, with no writing or comic experience beforehand. I was rushing to the end result instead of sitting and working with writing and art that I could work with and improve.
This is what I tend to think of when reflecting back on this 

I was delusional about my (non-existent) work! I had big ideas, but ideas don't make a good story, the execution does. And after working on my writing, and completing my script, it gave me a clear show of my strengths and made me want to make more work. No "big thing," it's literally just me entertaining myself. And people can form their own opinion on my work because it isn't just "brain idea," and has execution.
I've hit a point where I'm confident with my work and know it's good. Absolutely has flaws and things to improve on, but I feel I have concrete proof I can point to and go "these are my skills." Still delusional about my own work a little, I am my own number one fan. But I have the experience to know how to go about executing a big epic project in the future, and it's not some vague "I will one day!" only to be crushed by how difficult these projects are.
It's not that I think ambition is bad at all! Like I had a hell of a time with the ocs I had for that supposed magnum opus project, and I still have them and plan to write about them in the future. I think it does cause problems later on when jumping in headfirst can cause disappointment later if you're not prepared. I know I sure as hell would have been stressing with that project as a first one.
I just do find it a bit funny when I see this pattern repeat with other people, I just think "Ah, an unavoidable event."