We all have bad days when we feel low for no reason. No bloody reason. Normally a walk or a good film helps. I would not recommend shopping as a therapy. Yes talking to the best friend is therapeutic. If you are a woman I recommend you splash your favourite perfume to lift your spirits. And yes, a dash of colour on the lips will brighten up your face and mood too.
Perfume... my favorite is RED DOOR by Elizabeth Arden. Or Beauty by same.