Why $f\left(x\right)$ adds a space between f and the opening parenthesis while $f(x)$ does not? Is the space anyhow more correct typesetting for a function? If not, is there a way to remove the space added by \left( or prevent it from appearing?
This came as a huge surprise to me. Sorry if it is a duplicate, but I couldn't find anything similar.
Minimal working example:
\documentclass{article}
\usepackage[utf8]{inputenc}
\begin{document}
$f\left(x\right)$
$f(x)$
\end{document}
Sample output:

\leftadds a space by design (in most cases). Don't use it for function parentheses, it looks ugly – Mar 17 '18 at 22:31f\left(x\right)in the first place? – Mico Mar 17 '18 at 22:42\f{}, so I wanted the parentheses to be flexible. This was lost when writing the minimal example – Rafael Mar 17 '18 at 23:00