My experience over the last several months of updating and editing my site has been that small changes in one area will for some unknown reason lead to multiple blocks in other areas getting longer - essentially doubling in length, requiring the tedious 'reforming' of sections of blocks.
For example I can take a section of invisible (to the end user) code out of an embed, and then later discover adjacent text blocks have resized themselves, pushing or overlapping other blocks, and ruined the format/readability of the section. This can happen on any page, seemingly at any time. Can't figure out why exactly, because doesn't happen every time, but enough for me to have to google it and come here about it. Like Tankgurl said, very frustrating.