Beer is a national drink, period!
A default to order in a bar, the best friend to celebrate victories of the national basketball team, also the best medicine to calm the nerves if the latter accidentally lost.
Because it is rather easy to produce, because there are strong traditions, both of industrial production and "home brewing" in certain regions. Because we were not too spoiled with the selection of wines, whiskeys and liquers during pre-independence years.
Maybe Lithuanians are not famous for such a selection of beer sorts as Czech or Germans, but the taste is really good.
By the way, the beer is relatively cheap in the bars - 1,5EUR for a usual 0,5 litre mug.
And it is called "Alus" in Lithuanian. Make sure you know this word before coming for a visit!