If we were to read between the lines, Paul might be saying, "You Athenians are to be commended for your devotion to spiritual things." The King James' rendering of "religious" as "superstitious" exposes the latter word as having undergone what linguists call semantic drift. In Shakespeare's day and King James' time, this word did not have the negative connotation as it does now.
From the context of this account, it is plain that the apostle Paul was not, as some theologians like to characterize him, a feisty, wrangling, argumentative hothead. The men of Athens, who vastly outnumbered Paul and loved a good philosophical debate, could have made short work out of any know-it-all smart aleck. The apostle Paul was thus lavish in his compliments.
Throughout his ministry, he frequently resorted to diplomatic language. At one point, he acknowledged a cultural debt both to the Greeks and to barbarians (Romans 1:14). In addition to complimenting strangers, Paul continually sought out similarities he shared between him and other groups. In a conflict in which both the Sadducees and the Pharisees were breathing fire down his neck, Paul masterfully ingratiated himself to the Pharisees, reminding them that he and they shared the same view on the resurrection (Acts 23:6-8). Paul, to the right people, let it be known that he was a Roman citizen (Acts 16:37-39; 22:25-29).
We also need to find common ground, not only with people in the other groups of the church of God, but with the world at large, emphasizing (like mountains) the things we agree upon and de-emphasizing (like molehills) the things we disagree upon.
In the process of finding common ground, we dare not compromise our core values or syncretize them with the world. We should instead practice more of what one late church of God minister counseled, "You don't have to tell all you know." Oftentimes, keeping our traps shut is the most diplomatic behavior of all (Ecclesiastes 3:7; Lamentations 3:28-29; Amos 5:13).