How to reduce space between lines in a table

Sometimes (horizontal) space is jut too much in a LaTeX table.
In order to decrease it, it is actually possible to give negative values to addlinespce

\begin{tabular}{ll}

   Line1&some text\\

    \addlinespace[-0.3ex]

             Line1&some text\\

\end{tabular}

Original link:
https://tex.stackexchange.com/questions/268508/reduce-the-space-between-two-lines-in-a-latex-table

How to write new line in LaTeX

Many LaTeX user (as myself in the past) think that the form of new line is to write

\\

Well, it works, bit it is actually not new line, but starting a new paragraph
The correct notation for new line (but not new paragraph) is

\\*

A more detailed description with many other possibilities to write new line new paragraph, new page is available at
http://www.personal.ceu.hu/tex/breaking.htm#newline