If the HomeAssistant subreddit is anything to go by its their biggest complaint (HA configuration is in YAML).
With that said if they weren't complaining about white space they'd be complainit about missing semicolons, missing/extra commas, missig equals signs, missing closing )]} or whatever.
With that said if they weren't complaining about white space they'd be complainit about missing semicolons, missing/extra commas, missig equals signs, missing closing )]} or whatever.