The line's for real

Not infrequently, we get letters or blog-responses to individual poems published in Poetry that cite particular phrases or lines in order to prove somehow that a poem or poet (and, by implication, our taste) is lousy.  It's an invidious tactic, and it occurs to me that one can make any poem in the world look bad by pulling a line or so out of context.  Summer's here and the time is right for fun and games, so... shall we give it a try?  Are there any foolproof poets or poems?   Care to dissect a few?  So far, the only poem I can think of that seems immune is Blake's "The Tyger."  Or am I wrong about all this?