bookmarks and branches.
Coming from git to hg, it was a step back in time to branches that can’t ever actually be deleted and bookmarks are... not obvious.
Can you actually create two bookmarks on your current commit and then move forward on just one? who knows? I never figured it out.
What is it specific that you dont get ? I actually thought hg is conceptually simpler.
And hg to me has always felt BSD like, Git was Linux like. Unfortunately everything with BSD failed to gain any popularity. Including BSD license in itself. ( Yes I know Netflix are using it in their Edge Appliance )