Luby's Cafeteria is an amazing place. You can just walk in on any given day and chose from a wide variety of options, making almost any conceivable combination of food that seems appetizing at that particular moment. "Sure, I'll take some lasagna, fried okra, tortilla soup, cheesecake. And why don't you throw some jello in, just for good measure!"
Religious life is becoming increasingly similar to Luby's. You can find all sorts of people nowadays, from Buddhist-Episcopalians to Branch Davidians Muslims (no, seriously). I sincerely believe that diversity is a good thing because it raises awareness of our global village. But the goal is to live out our unique religious experiences in harmony with others, not to harmonize our religious experiences with those of others.
Paul reminds the Christians in Thessalonica how they had "turned to God" from their old ways of life. They made the deliberate and dedicated choice to be Christians in a pluralistic world. They were Christian-Christians. They had one thing on their cafeteria trays, the true and living God. Their meal of life was not a hodge-podge assortment, but the perfect combination of the Eucharistic bread and wine.