It's easy to mistakenly believe HN is meritocratic if you have enough HN celebrity for people to seek your comments out. My comments with the least thought behind them get the most upvotes. Those with the most thought pass by unseen.
It's a powerful disincentive for putting much thought into comments.
For example I do not think that http://news.ycombinator.com/item?id=4843141 is anywhere close to being the best comment that I've made in the last month, but I have to go back to http://news.ycombinator.com/item?id=4684916 to find one that is higher rated.