Why do you think some people are immediately liked when entering a new group and some are liked after you get?

Well, it could have to do with physical appearance... but I would speculate that the majority has to do with self esteem and displayed confidence. Being sure of yourself (and friendly) is ofter very attractive to other people. I think deep inside everyone hungers for that type of confidence and they are attracted to people to display it because they secretly wish they had those attributes.

Some people have charisma and confidence. Others don't.

Normal people would judge a person by how he looks on the first time they meet, and by their looks, the mind will try to guess the personality of the person, after the two person become friends, the mind now knows the real personality of the person, and chooses to either be good or bad to the person. So, don't be sad if you can't get along with people fast, when they know you well enough, you will be accepted.(If you have a good personality.)