So I commissioned a poll. To get a better sense of what religious practices make the nonreligious uncomfortable, I asked SurveyMonkey Audience to ask its panel to answer questions about acts of prayer that might be performed by an individual believer over the course of an ordinary day (praying the rosary on the bus, feeling led to pray for or with an acquaintance, etc.) rather than acts carried out by groups or the government (Nativity scenes at a courthouse, protests, etc.).1 You can see the data from all the responses at our GitHub.
Christians worried that their actions might cause offense, but they were often wrong about which actions were most likely to raise hackles.