There used to be a commenter here who would end all his comments with a closing paren, even though there had not been an opening paren. It led to a surprising number of flamewars! )

Edit: hmm, I couldn't really find any flamewars, but it did lead to objections:

https://news.ycombinator.com/item?id=8534213 (Oct 2014)

https://news.ycombinator.com/item?id=8533381 (Oct 2014)

https://news.ycombinator.com/item?id=6027549 (July 2013)

https://news.ycombinator.com/item?id=4990706 (Dec 2012)

https://news.ycombinator.com/item?id=4963264 (Dec 2012)

https://news.ycombinator.com/item?id=4943159 (Dec 2012)

https://news.ycombinator.com/item?id=4881400 (Dec 2012)

https://news.ycombinator.com/item?id=4765943 (Nov 2012)