Kernel development is fun. Machine learning is interesting. Search engines are interesting too. Anything can be interesting if you're interested in it :P
I don't care which language I'm using, as long as it's C (I've also been trying out Rust). Vim is the only usable text editor (I tried using VSCodium with Vim shortcuts, it just can't beat pure Vim).
UNIX is nice, but not perfect. spawn() > exec()/fork(), and a lettered VFS is simply the clearest.
Page rank is very cool. Too bad Google barely uses it anymore. I guess advertising is more important?
I keep forgetting to map the stack. Long live the kernel!