Surviving is part of running into bandits who try to kill you, some do it for your supplys, others do it just to kill you. Having players try to kill you makes the gameplay more realistic and exciting in my opinion. Then there are players who are friendly and may team up with you. When I get DayZ working again I will kill people who either don't respond to me, or are hostile. When Players only have an axe or I'll try to team up with them, knowing they're not a big threat (assuming I have a gun or axe aswell). But yea, having people try to shoot you is why DayZ is so awesome, and makes me feel like i'm really in a zombie apocalypse.