boxesvertical alignment
What's going on here, why are the TEXTs not aligned?
\documentclass{article}
\usepackage{pbox}
\begin{document}
\hrule
\pbox[c][20pt][b]{\textwidth}{TEXT\\ Short}
\pbox[c][20pt][b]{\textwidth}{TEXT\\ Long Text}
\pbox[c][20pt][b]{\textwidth}{TEXT\\ Short}
\pbox[c][20pt][b]{\textwidth}{TEXT\\ Long Text}
\hrule
\end{document}
I would definitely go the second way with $\displaystyle: I find that it looks strange to have something centered after a bullet. To get the vertical alignment correct, just add [t] after \begin{aligned}, where "t" means "top". (See also the top of page 8 of the User's guide for the amsmath Package.)
This is the default behaviour when using \arraystretch. The reason for this is that the contents inside a tabular (or array) is set with the traditional \baselineskip in mind, with the additional horizontal rule, making it seem like the entries are not vertically centered within each row. Modifying (increasing) \arraystretch exaggerates this apparent mis-alignment.
I would suggest inserting blank lines above/below the rows that need "air" like in the following MWE:
\documentclass{article}
\usepackage{array}% http://ctan.org/pkg/array
\usepackage{tabularx}% http://ctan.org/pkg/tabularx
\setlength{\parindent}{0pt}% No paragraph indent
\newcommand{\ccol}{\centering\arraybackslash}
\renewcommand{\tabularxcolumn}[1]{>{\ccol}m{#1}}
\begin{document}
\textbullet~No modification of \verb|\arraystretch|: \par
\begin{tabularx}{\linewidth}{m{2.1in}X}
\hline
[19:21] time to take the tree outside\newline
[19:21] but I just let him back in! &
[19:21] time to take the tree outside\\
\hline
\end{tabularx} \par\medskip
\textbullet~\verb|\arraystretch=4| \par
\renewcommand{\arraystretch}{4}%
\begin{tabularx}{\linewidth}{m{2.1in}X}
\hline
[19:21] time to take the tree outside\newline
[19:21] but I just let him back in! &
[19:21] time to take the tree outside\\
\hline
\end{tabularx} \par\medskip
\textbullet~\verb|\arraystretch=1| \par
\renewcommand{\arraystretch}{1}%
\begin{tabularx}{\linewidth}{m{2.1in}X}
\hline \\ \\\mbox{}%
[19:21] time to take the tree outside\newline
[19:21] but I just let him back in! &
[19:21] time to take the tree outside \\ \\ \\
\hline
\end{tabularx}
\end{document}
Note that using square brackets to start a new line in a tabular could lead to problems when inserting empty rows, since \\ is a control sequence that takes an optional argument: \\[<len>]. To avoid this, I've inserted an empty \mbox{} after \\ (in the last tabular) otherwise TeX would try to perform \\[19:21], and 19:21 is not a valid TeX length.
Best Answer
ginLonghas a depth where as inShortno letter has depth. This is why the misalignment comes. To correct it, you may add a\vphantom{g}toShortor\smashtheLong(or onlyg).