I initially found git a bit confusing because I was familiar with mercurial first, where a “branch” is basically an attribute of a commit and every commit exists on exactly one branch.

To be fair, Mercurial has some poor design choices which leads to a very different mental model of how things are expected to operate in Git. For starters, basic features such as stashing local changes were an afterthought that you had to install a plugin to serve as a stopgap solution.