I kind of echo the OP.
I have ideas that I want to try writing out. I need practice, so right now I'm just writing a story I came up with out of thin air to do so, but what started as an extremely simple premise with a couple of goals(character writing, and a few challenges, like having an Isekai protag that can't understand the language, for an example), has turned into a real story with tons of thought put into the backdrop, multiple plot threads going on now, and so much more.
All because people read it. It gave me joy, and I worked for that, making people happy makes me happy, the idea someone enjoyed my writing feels amazing, and somehow it blew up and got on trending, and because of that, I gained more people to feel excitement for with ever post, as I watch the list of recent readers catch up to the latest chapter.
I am incredibly humbled and so thankful for my readers, and every comment, most have been good but even that not great ones let me know that people care enough to leave any kind of comment. The most humbling of all is just the fact people are reading it.
I am still floored by how big a response I can get on my own now. I posted two chapters in one day and got a response that rivaled being #6 on trending. How fucking crazy is that? It blows my mind. I don't feel worth it. I feel like my work is shit, I criticize the hell out of myself, do I have things I'm happy about, even proud of? Yeah. But there are also always things I can berate myself on worse than any commenter could dream.
This, right here though, blows my mind so much.
The fact I hit trending so much is nuts in itself, but...
The fact I can release content and get a similar response is so nutty to me.
So, I am very much writing because people are enjoying it.
I thought a few dozen people were great, now I'm just ecstatic everytime I think about it.
I hope this feeling never dies. I love making people happy.
EDIT: This right here, my newly posted Chapter 16
This, is my joy, and my motivation.
"I like it when you smile, ..." - Quote from Chapter 14, and the title.