* Going into advisor meeting thinking ho-hum, nothing to report, just hacking on proofs still, and having a gaping-sucking-wound counterexample open up in proofs that undermines absolutely everything when Frank points out a weirdness with unification.
* Having writing critiqued by people who certainly read enough to be competent critics, even though I tried really hard not to care too much, because, well, I'm not and not aiming to be a professional writer or anything like that. Which is different from not caring at all.
* Finding out that there may be a simple fix, although it sacrifices some elision opportunities I would have like to have had.
* Realizing that at least I'm not writing a novel's worth of fan fiction.