More than once I've found that the first people to approach you when you enter a new environment are not the people you want to be with. Some people actively come after you to try and pull you into their circle of influence. Often this is because they have found themselves struggling to fit in, or vying for power in the in group.

Going after the new people is a seemingly easy way to garner influence. It can take time to get to know people, and for people who are only there temporarily, it's fine, but if you're in there for the long haul, take the time to truly get to know people and to know their motives for going after you. They may be poisonous people, and I'd argue that more often than not these people are the first to approach you if you're new. Tread carefully.