"Awesome post." Great! Show your support with an upvote. Bam.
"Too hungover to read all that today though. Definitely Saturday morning over a cup of coffee - assuming I'm not in the same shape then." This contributes in no way, shape, or form to promoting insightful and educational discussion.
There's definitely a school of thought on HN which would say so. Upvotes are a fine proxy for appreciation. Other online communities have taken steps to remove verbose "+1" mechanisms too - for example, GitHub, as per demand, added the ability to respond "+1" to comments without having to write an entirely new comment. That indicates that consumers of GitHub (and most HN users are probably in that demographic) value brevity.
Personally, I suspect a post saying only "Awesome post" would have garnered 0 or only a couple downvotes. However, the hangover comment was - in my opinion - a bit self-indulgent, irrelevant, and not in any of the broad categories of things people come on HN to find.
Just try not to humble brag or add 0 or negative valued commentary. No one gives a rats ass about your hangover, when you'll read the article, we care about comments about the article when read now..