Nice story. Personally, if I make something even remotely successful, I don't think I would feel guilty. But, I would try to participate a bit more on open source project (especially the ones I leveraged my app with).
Regarding your Postgres GUI, I use HeidiSQL at home and at the office, it works with both MySQL and Postgres (and a few others). Best client in my opinion, but the support for Postgres is not perfect. Otherwise, there is a client included with Postgres server package when you install it. (at least on Windows)