The bad has to go for the good to come

Question of the day:
What's the best way to comfort someone who's having a bad day? (A situation when a girl is having a bad day)

Answer:
Some people don't really feel like talking about it, let them be. She might feel uncomfortable talking about it. In some situation she might want to rant at someone vent her anger, do not hesitate to be her listening ear. This will definitely make her feel better instead.
Do not joke about it, she will think that you're trying to insult her, and that will trigger her mood when she is already in a bad one.
Pay full attention to what she's complaining about, take in mind that we should pay attention to the small details, because it is a good thing that we can remember these details..
The best thing (If everything allows) is to hear her up, and shoulder some of her burden, plus some words of encouragement.. This is how I feel..