<p>I do not know if it is a memorable answer by the overall standards of CV, but the accpeted one here is the one I found most useful of all questions I have asked:</p>

<p><a href="https://stats.stackexchange.com/questions/139001/example-for-a-prior-that-unlike-jeffreys-leads-to-a-posterior-that-is-not-inva">Example for a prior, that unlike Jeffreys, leads to a posterior that is not invariant</a></p>

<p>[Bounty started 9 Feb 2016. Now awarded.]</p>
