restlessness

i was hanging out with a friend last night and i asked her a question with led into a night of restlessness. i asked her Why is it that people can choose a family member or other people and they can choose a boyfriend over other people but choosing a friend over other people is forbidden? i have been wrestling with this question for a long time because it makes no sense to me why there are only certain people that are allowed to be a prioty in ones life. it just makes not sense to me and i was up all night thinking about it and if i agreed with her answer.