Perfect example: https://news.ycombinator.com/item?id=30246830&p=2#30247139
Write the one liner and then imagine you got a moderator scolding. Then write a comment defending your one liner from the charge of 'unsubstantiveness'. Finally, delete the one liner and post the defense.
I bet you'd almost never get scolded for these and the upvotes would be even bigger.