What does "Going Extra Miles" mean?

Not everyone likes dogs, and for those who do, not all of them keep a pet dog for various known and unknown reasons. But, I spoke to a lady, she doesn't like dogs, but for the sake of friendship, she was even taking care of a dog at her own residence for her female friend who was outstation for several days. The dog is used to sleeping with her owner, but she can't imagine allowing the dog to sleep with her on her bed, so she had to sleep on the sofa in the living room, and that is certainly not too comfortable to promote any restful sleep. Frankly, would you go to this extend to help your friend? She is taking the friendship so seriously to even go the extra miles to take care of the dog, when in the first place she does not even like dogs. There is a price to pay for going the extra miles. But, I suppose it pays in other ways.