I have yet to ascend to the heights of university education, and before I do, I would like to clear something up:
As I was revisiting a book on complex analysis, I see questions like the following:
Show that if $f(z)$ is holomorphic on $\mathbb{C}$ (entire) and $f(z)\not \in \mathbb{R^+}\cup \{0\} $ for all $z\in \mathbb{C}$, then $f(z)$ itself is constant.
The usual method is to observe that $g(z)=\ln(f(z))$ is holomorphic, and that the imaginary part of $g(z)$ is bounded, but suppose that in a college exam I were to write: "Picard's Theorem: QED" (and perhaps a line or two to show that I know what it means, although I have no idea how to prove it). Would I lose points and be disciplined? Are professors annoyed about such things?
I am thinking about such questions because I did not see the elementary solution immediately, and I suppose that one does not enjoy the privilege of time in an exam, with the air conditioning freezing one's hands and grades to fret about.