One thing that doesn't seem to have been mentioned is the fundamental differences between beer (ale) & lager. They are two significantly different strains of yeast. Ale yeast is a top-fermenting strain, lager bottom-fermenting. Whether that has any relationship to the different drinking temperatures, I don't know!

But lager is brewed to be drunk cold i.e. around 4C, which explains why warm lager tastes like piss... ;-) Beer (ale), as previously noted, is brewed to be drunk at 10-14C; cool, not chilled; so that you can taste the bloody stuff! ;-)