Jambun, I had to laugh when I read the phrase that the team who got penalized for the PF "must have voiced some sort of objection."
So, with that in mind, and recognizing that all officials have different tolerance levels, what's the general rule of thumb for when words and/or actions rise to the level of a personal foul? Clearly, coaches voice their displeasure with calls (and non-calls) all the time without triggering a PF. What's the trigger? Curse words? Volume level? Continuing beyond a certain point (i.e., after the official looks over and says "that's enough, Coach")?
Do you/officials tend to give a coach a little more leeway if you/they start having reservations about the call in dispute?
Last, and looking at it from the other side of the issue, what's the most effective way a coach can communicate to an official that he 'respectfully disagrees' with the call that just got made/missed?