In my experience being aggressive or patronising tends to cause people to become combative which in turn makes them (subconsciously or otherwise) less likely to

In my experience being aggressive or patronising tends to cause people to become combative which in turn makes them (subconsciously or otherwise) less likely to actually understand the point you're trying to make and more likely to waste time trying to convince you of their point. I find that presenting your case in a calm and relatively neutral way (note not "wrapped to avoid being upsetting in any way ...", that's a false dichotomy in my opinion) tends to be the most effective approach overall.