In "Ex-Basketball Player" what does this mean: "Flick stands tall among the idiot pumps - five on a side, the old bubble head style."
This important quote comes from the second stanza that introduces us to the character of Flick. It is important to read the quote you have singled out in context of the whole poem and the stanza in which it occurs to understand what Updike is trying to do with this reference:
Flick stands tall among the idiot pumps -
Five on a side, the old bubble-head style,
Their rubber elbows hanging loose and low.
In this stanza, therefore, Updike is personifying the pumps and making them seem if they were alive and also comparing them to Flick. Note how the alliteration of "loose and low" and the description makes them appear as basketball players themselves. Updike seems to be reinforcing the theme by focussing on what Flick has become - he may have had skill once, but now he is nothing more than a gas pump attendant with all of that skill unused and amounting to nothing.