I always try to be polite and cede the area to the other group if they were there first for all content, unless it is an obvious contested mob like HNM in XI were (as far as I know there is nothing like that in XIV at the moment due to short respawn and variety of content).

However that being said I have 2 speeds, polite and "I will crush you" depending on how others react and act towards me.

And I will crush you.