People are much better at not committing the planning fallacy (in the underestimating direction, at least) when estimating other people's timelines for a given task, so I'd say absolutely it's a social thing. There's immense social pressure to give a rosy view of yourself; you wouldn't want to disappoint, would you?
There doesn't seem to be any archive of this particular post, but the comments are intact here at least: https://www.greaterwrong.com/posts/G78CnAYMLbWEDKj6w/diachronic-done-right
(you'll need to open this with copy/paste; LW is too clever and replaces the link's actual URL with lesswrong.com, which doesn't have the comments. Gotta open it on greaterwrong.)
Responding to this on the point of feelings/bids/etc:
One problem I run into a lot is that I want to just say X, but it's fo freakin' difficult to do so without also accidentally saying Y. The default solution is to put a boatload of effort into crafting what I'm saying to evoke the correct response in the other person, but this is difficult and failure-prone. So if we don't go that route, in order to communicate what I mean to communicate and not also something else, it takes some cooperation between both parties — I promise that I jus...
I'm pretty disappointed in how hidden the San Francisco event was. I was looking forward to the possibility, but nothing on Google or even Less Wrong gave any indication that it existed (except in the hypothetical and previous years). I was sad to discover after the fact that there was one, but I /still/ can't find details for it.
Here's an Archive.org copy of the broken Method of Rotation/Kierkegaard post