People need to understand the difference between depression: the emotion, and depression: the disorder. If you've never had clinical depression, you have no right to act as though you know what the **** you are talking about. Just because someone doesn't carry a big flag prolaiming their disorder (wheelchair, crutches, seeing eye dog...) doesn't mean they're making it up. You can't cure clinical depression by having sex or playing with a puppy, just like you can't cure dyslexia, autism, or down syndrome by doing the same things.
As far as a cure for depression, try this on for size.