[chriswarbo]

> Developers will go through extraordinary lengths to avoid making things global, but the truth is that for end-user applications a great deal of the relevant product requirements are essentially singletons.

Globals are appropriate when "there can be only one"; however, I tend to find that's rarely the case. Much more common is "there can be only one at a time"; in which case, dynamic variables are far more useful than global variables. The most obvious example is in tests.