Question: why does mercury not wet anything it touches?

Paul Brack answered on 19 Jun 2015:

Mercury atoms much prefer each other than other things, like glass, for example. So rather than stick to, or in other words, wet their surroundings, mercury atoms just stick to each other, and don’t wet things. In contrast, water molecules are more attracted to eg glass than they are attracted to each other, and thus they do wet surfaces.