Requiring a blank line between a paragraph and list

Yep, this is the most common mistake I see people making who are new to markdown as well.

I have never noticed it implemented any other way in practice, so I’ve gotten used to it.

The topic linked above has a number of legitimate reasons not to consider line breaks as new paragraphs by default in general, so its worth a read.

If lists could be special without any major pitfalls I think it would better meet user expectations.

especially when the "treat line breaks as paragraphs option is used"
like
this.