A serious question indeed brother, one worthy of serious reflection. One should, of course, always expect and demand a decent beer when one slides hard-earned coin of the realm across the bar. However, in certain circumstances, one should drink in that bar. One should never refuse a free beer ... so, if one's buddy invites one to step into a pub where the beer is known to be sub-standard, and says "I'll buy", of course one would drink in that establishment. It is indeed a clash of values and standards; but bottom line is: free beer is good.
I think I'll pull another cold Dead Elephant out of the fridge, spark up a fat one, and give this dilemma more thought.