I enjoy how well-crafted Fossil seems to be; just like SQLite, which a sibling comment also mentioned. I really want to use Fossil, but it would be way too hard for me to not have the index/staging area of Git. [1] For all the software that claims to be 'opinionated', Fossil really is that.
[1]: https://fossil-scm.org/home/doc/trunk/www/gitusers.md