People take advantage to increase in some situations like in jobs, schools or in other activities . Those are interested in making friends to take advantage of something and want to be friendly with them.
Taking advantage of someone is common among people.This kind of situation happened me when i was in school. There was a genius girl in our class and for my group of friends , it was a great idea to make us friend of her to get better grades. Obviously,she would help us to do the tasks of school. We decided invite her to a party but she refused to go. Next time, another a idea came to our mind to make her birthday ,it made her happy and she joined with us.
To take advantage of someone is not appropriate, that person can feel betray and never trust in other.it would not like if someone wants to be friendly with us for some reason.