I always get a good chuckle when I see comments that get unexpectedly processed as a new ordered list. Like if replying to a 3-item comment by starting with "4. " which renders as "1. " -- for the sake of users who don't know these nuances of markdown, I wish it strayed a bit further to accommodate them.

Bold, italics, links, etc. -- sure, false positives there are rare enough and the means of correcting mishaps are intuitive enough. The OL issue though... so many go uncorrected.