IPA:  India Pale Ale.  This is an English Beer Style.  It gets it's name from a pre-industrial time when England was occupying India.  The troops supplied a great demand for pale ale in India, but the beer rarely survived the long voyage across hot seas in the wooden ships.  Ales with more hops were fairing better, so brewers began adding more and more hops to the pale ale.  With this they were enjoying greater success at getting good beer to India.  As years went by and troops were returning to England, they found that they greatly preferred the pale ale they were getting in India to that pale ale that was still being served in England.  They wanted the India Pale Ale.  The rest, as they say, is history.  IPA is now one of the most popular ale styles served in the United States.  Many beer aficionados judge a brewery on the quality it's IPA.  Aggressive, hoppy, fresh IPA is a sign that you are a forward leaning brewery with a good understanding of style and history.  Thin, watery, weak IPA shows that your brewery is ran by your marketing team who will all tell you, "hops are bitter and people have a natural aversion to bitterness".  What they are failing to take into account is that hops are good for you, and over time people come to prefer that hoppy bitterness.  It is an excellent example of an acquired taste.