Two Remarks

One of which is about analysis, and the other about organic lab.

1. In a metric space, a sequence can be both Cauchy and not converge to anything in the space! The way this is done makes me groan, though (essentially, find a Cauchy sequence that coverges to a limit in the metric space, then re-define the space to be missing that limit point. Kind of "cheating", but it works).
2. Yes, there were plenty of diethyl ether fumes in the lab, redolent of memories of fruit-fly crossing experiments. How do you all work with this stuff? It is so volatile that a solute will start precipitating at the edges almost as soon as it's dissolved. My yields are horrible*. Grr. The atmosphere of the lab is palpably more relaxing than the analytical lab, though (less lab prep, less emphasis on lab technique, etc.).

*Well, ok, one of the other reasons my yields are really bad is because an incidental minor gust of wind blew half my product off my watch glass all over the countertop.