You need to be in a jungle. According to the wiki (Usually, I would know about mobs, but I never search for ocelots):
Ocelots try to spawn on grass blocks or leaves at sea level or higher in jungle biomes. There is a 1⁄3 chance that a spawn attempt will fail.
Ocelot kittens can also be found randomly - two occasionally spawn with an adult ocelot. With the exception of a faster movement rate, ocelot kittens obey the same behavior as adults.
/e Far as the hostile mobs, sounds like it may be a server setting. It's like that on a few servers I've been on, but others would have a constant spawning of them no matter how many people were on.
This post was edited by CHunter on Sep 6 2015 06:00pm