This is a hard question.
For me, it is hard to say, because I think of the way I acted when I was younger, when it came time to make friends. I was always wary of others... took me a very long time to open up... I know I could be very frustrating to people who wanted to be my friend. It took a very long time to earn my friendship... but it could be ended very quickly.
I like to think I was "worth the effort" to my friends... once they had earned my friendship, I will do anything for them, I was very loyal. Earning it can make it hard for the person who has to do the earning... but it can be worth it. Some people need to be 'earned', they need it to be shown to them that the other person in the friendship will invest time and care into it.
Not really sure that answered your question, sorry.

((( Freewill )))