(Glorified) CVS brain rot
If you come at Mercurial with a Subversion mindset, things will almost work, but when they don’t, you’ll be confused, unhappy, and unsuccessful, and you’ll hate Mercurial.
Whereas if you free your mind and reimagine version control, and grok the zen of the difference between thinking about managing the versions vs thinking about managing the changes, you’ll become enlightened and happy and realize that this is the way version control was meant to work.
Git doesn’t have a high learning curve. [Subversion] has a high unlearning curve. Observe the difference in those familiar with neither.
This is too important to miss out on. This is possibly the biggest advance in software development technology in the ten years I’ve been writing articles here.