5 years of experience, yet still not clue what "Underfull \hbox" means
Context: LaTeX is a typesetting system. When compiling a document, a lot of really in-depth debugging information is printed, which can be borderline incomprehensible to anyone but LaTeX experts. It can also be a visual hindrance when looking for important information like errors.
If you work with LaTeX for five years and still have no idea what a hbox is or what that message means, you should not consider naming this "experience".
I already explained this in my post of yesterday in this thread. I've been the TeX admin at our university in my student times. I've been creating styles and \shipout macros. I know this stuff inside out. Heck, I've even read good parts of the source to understand some finer points.
"Using LaTeX" and "programing with LaTeX" are very different things. For most people, LaTeX is a means to an end, for you LaTeX is your whole job. You're the exception, and exception can not be an example.