Islam Q&A (article 88206) writes about Muslims eating kosher meat, quoting Shaykh Ibn 'Uthaymeen:
It is not essential to ask about that which was slaughtered by a Muslim or a kitaabi, and how it was slaughtered, and whether the name of Allaah was mentioned over it or not. Rather that should not be done, because that is being obstinate in religious matters. ...
Question: What does not being "obstinate in religious matters" mean in everyday life?
Obviously, there's certain things we should and should not do regardless of whether or not we're being obstinate. The above (eating kosher meat) is one example, and I'm seeking an answer which expands on this with further examples and how to apply it to everyday life. (Perhaps avoiding drinking coke or listening to music would be examples of being obstinate in religious matters.)
At which point do we say enough is enough, and declare that we're in danger of being obstinate?