I make things I want to use, Last year I fully made the following projects then took them offline and saved for a later date when I have free time to maybe make a real project.
AI A search engine AI that indexed 90 million web pages before I archived everything
Mail Client with Antispam Fully working mobile ready mail client with anti spam that was online based, able to auto detect spam and filter, and full send mail abilities.
A few games I like building them, not playing them often.
And now I am working on a project that is always online called SimpleScript a coding language thats designed to be simple and easy to learn. I host it at codesimplescript.com and writing docs as I build it is a challenge for me, but I am finding it fun. I yesterday got full nested ARRAY variables working.
My goal is to make SS a langue I can use, with it already supporting Templates in a easy way and a admin panel to update SS and also in the future monitor your site usage and performance in real time.
Whats important Build WHAT YOU WANT!! What you may use but not like, and have fun building it.