Was he there before you were? Because it's common courtesy to world hop when someone is already occupying a busy spot (slayer monsters, mining rocks, etc) If I was there first, I would be angry as well. I understand that there is no written rule saying you can't swoop in a take all the (monsters, resources) but it's impolite to do so. As well as frowned upon by a large majority of players. You need to think of how you would feel if someone showed up and started (killing, collecting) everything you were. You might have a system or something of that nature going, and then this person comes along and interrupts it. I'm sure you would be angry at said person. If you were there first, then the above statement is rendered moot.